diff --git a/project_estimation/README.rst b/project_estimation/README.rst
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+==================
+Project Estimation
+==================
+
+.. 
+   !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+   !! This file is generated by oca-gen-addon-readme !!
+   !! changes will be overwritten.                   !!
+   !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+   !! source digest: sha256:0faffaf36b0c57e81ee69946cb1d5445d5dae4f3efa82e3e0219d5f7a1fec03e
+   !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+
+.. |badge1| image:: https://img.shields.io/badge/maturity-Alpha-red.png
+    :target: https://odoo-community.org/page/development-status
+    :alt: Alpha
+.. |badge2| image:: https://img.shields.io/badge/licence-AGPL--3-blue.png
+    :target: http://www.gnu.org/licenses/agpl-3.0-standalone.html
+    :alt: License: AGPL-3
+.. |badge3| image:: https://img.shields.io/badge/github-OCA%2Fproject-lightgray.png?logo=github
+    :target: https://github.com/OCA/project/tree/18.0/project_estimation
+    :alt: OCA/project
+.. |badge4| image:: https://img.shields.io/badge/weblate-Translate%20me-F47D42.png
+    :target: https://translation.odoo-community.org/projects/project-18-0/project-18-0-project_estimation
+    :alt: Translate me on Weblate
+.. |badge5| image:: https://img.shields.io/badge/runboat-Try%20me-875A7B.png
+    :target: https://runboat.odoo-community.org/builds?repo=OCA/project&target_branch=18.0
+    :alt: Try me on Runboat
+
+|badge1| |badge2| |badge3| |badge4| |badge5|
+
+This module is a pre-sales module designed to manage project cost
+estimation before confirming a Sales Order.
+
+In many service-based businesses, project discussions start with rough
+calculations, scope alignment, and internal margin validation. Creating
+a full Project too early can mix pre-sales assumptions with confirmed
+execution data. This module separates the estimation phase from the
+execution phase.
+
+The purpose of this module is to:
+
+- Provide a structured space for cost calculation before commitment
+- Allow internal validation of pricing and margin
+- Prevent pollution of confirmed Project data with unvalidated
+  assumptions
+- Enable clean conversion to Sales Order once approved
+
+This module represents the commercial negotiation stage, not the
+operational delivery stage.
+
+Once the estimation is validated and approved, it can be converted into
+a Sales Order. If the deal does not proceed, the estimation can simply
+be cancelled without impacting project reporting.
+
+.. IMPORTANT::
+   This is an alpha version, the data model and design can change at any time without warning.
+   Only for development or testing purpose, do not use in production.
+   `More details on development status <https://odoo-community.org/page/development-status>`_
+
+**Table of contents**
+
+.. contents::
+   :local:
+
+Usage
+=====
+
+To use this module, you need to:
+
+1. Go to menu Project > Estimation
+2. Create a new Project Estimation
+3. Add estimation lines such as services, materials, or working hours.
+   For each line, define quantity, cost, and price.
+4. Review the overall estimation. Adjust pricing or quantities until the
+   expected margin meets business requirements.
+5. Once internally validated, confirm the estimation.
+6. Click Create Sales Order. It will generate a Sales Order based on the
+   estimation lines, and the standard sales workflow continues from
+   there.
+7. If the deal does not proceed, simply cancel the estimation. No
+   Project or accounting records will be affected.
+
+Bug Tracker
+===========
+
+Bugs are tracked on `GitHub Issues <https://github.com/OCA/project/issues>`_.
+In case of trouble, please check there if your issue has already been reported.
+If you spotted it first, help us to smash it by providing a detailed and welcomed
+`feedback <https://github.com/OCA/project/issues/new?body=module:%20project_estimation%0Aversion:%2018.0%0A%0A**Steps%20to%20reproduce**%0A-%20...%0A%0A**Current%20behavior**%0A%0A**Expected%20behavior**>`_.
+
+Do not contact contributors directly about support or help with technical issues.
+
+Credits
+=======
+
+Authors
+-------
+
+* Ecosoft
+
+Contributors
+------------
+
+- `Ecosoft <https://ecosoft.co.th>`__:
+
+  - Saran Lim. saranl@ecosoft.co.th
+
+Maintainers
+-----------
+
+This module is maintained by the OCA.
+
+.. image:: https://odoo-community.org/logo.png
+   :alt: Odoo Community Association
+   :target: https://odoo-community.org
+
+OCA, or the Odoo Community Association, is a nonprofit organization whose
+mission is to support the collaborative development of Odoo features and
+promote its widespread use.
+
+.. |maintainer-Saran440| image:: https://github.com/Saran440.png?size=40px
+    :target: https://github.com/Saran440
+    :alt: Saran440
+
+Current `maintainer <https://odoo-community.org/page/maintainer-role>`__:
+
+|maintainer-Saran440| 
+
+This module is part of the `OCA/project <https://github.com/OCA/project/tree/18.0/project_estimation>`_ project on GitHub.
+
+You are welcome to contribute. To learn how please visit https://odoo-community.org/page/Contribute.
diff --git a/project_estimation/__init__.py b/project_estimation/__init__.py
new file mode 100644
index 0000000000..25aa51eca4
--- /dev/null
+++ b/project_estimation/__init__.py
@@ -0,0 +1,4 @@
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl.html).
+
+from . import models
+from . import wizard
diff --git a/project_estimation/__manifest__.py b/project_estimation/__manifest__.py
new file mode 100644
index 0000000000..0537286140
--- /dev/null
+++ b/project_estimation/__manifest__.py
@@ -0,0 +1,24 @@
+# Copyright 2026 Ecosoft Co., Ltd (https://ecosoft.co.th/)
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl.html).
+
+{
+    "name": "Project Estimation",
+    "summary": "Pre-sales project cost estimation and margin calculation",
+    "version": "18.0.1.0.0",
+    "license": "AGPL-3",
+    "author": "Ecosoft, Odoo Community Association (OCA)",
+    "website": "https://github.com/OCA/project",
+    "depends": ["project", "sale_project"],
+    "data": [
+        "data/sequence.xml",
+        "security/project_estimation_security.xml",
+        "security/ir.model.access.csv",
+        "security/res_groups.xml",
+        "wizard/create_sale_order_view.xml",
+        "views/res_config_settings_views.xml",
+        "views/project_estimation_views.xml",
+        "views/sale_order_view.xml",
+    ],
+    "development_status": "Alpha",
+    "maintainers": ["Saran440"],
+}
diff --git a/project_estimation/data/sequence.xml b/project_estimation/data/sequence.xml
new file mode 100644
index 0000000000..4cd5b41c7c
--- /dev/null
+++ b/project_estimation/data/sequence.xml
@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<odoo noupdate="1">
+    <record id="project_estimation_code_seq" model="ir.sequence">
+        <field name="name">Project Estimation</field>
+        <field name="code">project.estimation</field>
+        <field name="prefix">PEST</field>
+        <field name="padding">5</field>
+        <field name="company_id" eval="False" />
+    </record>
+</odoo>
diff --git a/project_estimation/models/__init__.py b/project_estimation/models/__init__.py
new file mode 100644
index 0000000000..de8b62d126
--- /dev/null
+++ b/project_estimation/models/__init__.py
@@ -0,0 +1,6 @@
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+
+from . import res_config_settings
+from . import project_estimation
+from . import project_estimation_line
+from . import sale_order
diff --git a/project_estimation/models/project_estimation.py b/project_estimation/models/project_estimation.py
new file mode 100644
index 0000000000..bbae514a4b
--- /dev/null
+++ b/project_estimation/models/project_estimation.py
@@ -0,0 +1,214 @@
+# Copyright 2026 Ecosoft Co., Ltd (https://ecosoft.co.th)
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+
+from odoo import api, fields, models
+from odoo.exceptions import UserError
+
+
+class ProjectEstimation(models.Model):
+    _name = "project.estimation"
+    _inherit = ["mail.thread", "mail.activity.mixin"]
+    _description = "Project Estimation"
+    _order = "name desc"
+
+    name = fields.Char(
+        default="/",
+        required=True,
+        copy=False,
+    )
+    partner_id = fields.Many2one(
+        comodel_name="res.partner",
+        required=True,
+        tracking=True,
+    )
+    project_id = fields.Many2one(
+        comodel_name="project.project",
+        tracking=True,
+    )
+    sale_order_ids = fields.One2many(
+        comodel_name="sale.order",
+        inverse_name="project_estimation_id",
+        copy=False,
+    )
+    date = fields.Date(
+        string="Estimation Date",
+        default=fields.Date.today,
+        required=True,
+        tracking=True,
+    )
+    user_id = fields.Many2one(
+        comodel_name="res.users",
+        string="Responsible",
+        default=lambda self: self.env.user,
+        tracking=True,
+    )
+    company_id = fields.Many2one(
+        comodel_name="res.company",
+        required=True,
+        default=lambda self: self.env.company,
+    )
+    currency_id = fields.Many2one(
+        comodel_name="res.currency",
+        compute="_compute_currency_id",
+        store=True,
+    )
+    line_ids = fields.One2many(
+        comodel_name="project.estimation.line",
+        inverse_name="estimation_id",
+        string="Estimation Lines",
+        copy=True,
+    )
+
+    amount_untaxed = fields.Monetary(
+        string="Untaxed Amount", store=True, compute="_compute_amounts", tracking=5
+    )
+    amount_tax = fields.Monetary(string="Taxes", store=True, compute="_compute_amounts")
+    amount_total = fields.Monetary(
+        string="Total", store=True, compute="_compute_amounts", tracking=4
+    )
+
+    total_cost = fields.Monetary(
+        compute="_compute_totals",
+        store=True,
+    )
+    total_margin = fields.Monetary(
+        compute="_compute_totals",
+        store=True,
+    )
+    total_margin_percent = fields.Float(
+        string="Total Margin (%)",
+        compute="_compute_totals",
+        store=True,
+    )
+    target_margin = fields.Float(
+        string="Target Margin (%)",
+    )
+    target_sale_price = fields.Monetary(
+        compute="_compute_target_sale_price",
+        store=True,
+    )
+    expected_profit = fields.Monetary(
+        compute="_compute_expected_profit",
+        store=True,
+    )
+    state = fields.Selection(
+        selection=[
+            ("draft", "Draft"),
+            ("confirm", "Confirmed"),
+            ("approved", "Approved"),
+            ("done", "Done"),
+            ("cancelled", "Cancelled"),
+        ],
+        default="draft",
+        tracking=True,
+    )
+    note = fields.Html(string="Notes")
+
+    @api.depends("line_ids.price_subtotal", "currency_id", "company_id")
+    def _compute_amounts(self):
+        AccountTax = self.env["account.tax"]
+        for rec in self:
+            lines = rec.line_ids.filtered(lambda x: not x.display_type)
+            base_lines = [
+                line._prepare_base_line_for_taxes_computation() for line in lines
+            ]
+            AccountTax._add_tax_details_in_base_lines(base_lines, rec.company_id)
+            AccountTax._round_base_lines_tax_details(base_lines, rec.company_id)
+            tax_totals = AccountTax._get_tax_totals_summary(
+                base_lines=base_lines,
+                currency=rec.currency_id or rec.company_id.currency_id,
+                company=rec.company_id,
+            )
+            rec.amount_untaxed = tax_totals["base_amount_currency"]
+            rec.amount_tax = tax_totals["tax_amount_currency"]
+            rec.amount_total = tax_totals["total_amount_currency"]
+
+    @api.depends("company_id")
+    def _compute_currency_id(self):
+        for rec in self:
+            rec.currency_id = rec.company_id.currency_id
+
+    @api.depends("line_ids.price_subtotal", "line_ids.margin", "line_ids.cost_subtotal")
+    def _compute_totals(self):
+        for rec in self:
+            rec.total_cost = sum(rec.line_ids.mapped("cost_subtotal"))
+            rec.total_margin = sum(rec.line_ids.mapped("margin"))
+            rec.total_margin_percent = (
+                rec.amount_untaxed and rec.total_margin / rec.amount_untaxed
+            )
+
+    @api.depends("total_cost", "target_margin")
+    def _compute_target_sale_price(self):
+        for rec in self:
+            margin = rec.target_margin
+            if margin >= 100:
+                rec.target_sale_price = 0.0
+            elif margin > 0:
+                rec.target_sale_price = rec.total_cost / (1 - margin / 100)
+            else:
+                rec.target_sale_price = rec.total_cost
+
+    @api.depends("target_sale_price", "total_cost")
+    def _compute_expected_profit(self):
+        for rec in self:
+            rec.expected_profit = rec.target_sale_price - rec.total_cost
+
+    @api.model_create_multi
+    def create(self, vals_list):
+        for vals in vals_list:
+            if vals.get("name", "/") == "/":
+                vals["name"] = (
+                    self.env["ir.sequence"].next_by_code("project.estimation") or "/"
+                )
+        return super().create(vals_list)
+
+    def action_confirm(self):
+        return self.write({"state": "confirm"})
+
+    def action_approve(self):
+        return self.write({"state": "approved"})
+
+    def action_cancel(self):
+        return self.write({"state": "cancelled"})
+
+    def action_done(self):
+        return self.write({"state": "done"})
+
+    def action_draft(self):
+        return self.write({"state": "draft"})
+
+    def action_create_sale_order(self):
+        """Open wizard to create a Sale Order from the estimation."""
+        self.ensure_one()
+        if not self.line_ids:
+            raise UserError(self.env._("Please add at least one estimation line."))
+        return {
+            "name": self.env._("Create Sale Order"),
+            "type": "ir.actions.act_window",
+            "res_model": "project.estimation.create.sale.order",
+            "view_mode": "form",
+            "target": "new",
+            "context": {
+                "default_estimation_id": self.id,
+            },
+        }
+
+    def action_view_sale_order(self):
+        self.ensure_one()
+        return {
+            "name": self.env._("Sale Order"),
+            "type": "ir.actions.act_window",
+            "res_model": "sale.order",
+            "view_mode": "list,form",
+            "domain": [("project_estimation_id", "=", self.id)],
+        }
+
+    def action_view_project(self):
+        self.ensure_one()
+        return {
+            "name": self.env._("Project"),
+            "type": "ir.actions.act_window",
+            "res_model": "project.project",
+            "view_mode": "form",
+            "res_id": self.project_id.id,
+        }
diff --git a/project_estimation/models/project_estimation_line.py b/project_estimation/models/project_estimation_line.py
new file mode 100644
index 0000000000..394f6b2cc6
--- /dev/null
+++ b/project_estimation/models/project_estimation_line.py
@@ -0,0 +1,236 @@
+# Copyright 2026 Ecosoft Co., Ltd (https://ecosoft.co.th)
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+
+from odoo import api, fields, models
+
+
+class ProjectEstimationLine(models.Model):
+    _name = "project.estimation.line"
+    _description = "Project Estimation Line"
+    _order = "sequence, id"
+
+    estimation_id = fields.Many2one(
+        comodel_name="project.estimation",
+        required=True,
+        ondelete="cascade",
+    )
+    sequence = fields.Integer(default=10)
+    display_type = fields.Selection(
+        selection=[
+            ("line_section", "Section"),
+            ("line_note", "Note"),
+        ],
+        default=False,
+    )
+    name = fields.Char(
+        string="Description",
+        compute="_compute_name",
+        store=True,
+        readonly=False,
+        required=True,
+        precompute=True,
+    )
+    product_id = fields.Many2one(
+        comodel_name="product.product",
+    )
+    cost_type = fields.Selection(
+        selection=[
+            ("labor", "Labor"),
+            ("material", "Material"),
+            ("service", "Service"),
+            ("overhead", "Overhead"),
+        ],
+    )
+    product_uom_qty = fields.Float(
+        string="Quantity", digits="Product Unit of Measure", default=1.0
+    )
+    product_uom_id = fields.Many2one(
+        comodel_name="uom.uom",
+        string="UoM",
+        domain="[('category_id', '=', product_uom_category_id)]",
+    )
+    product_uom_category_id = fields.Many2one(related="product_id.uom_id.category_id")
+    unit_cost = fields.Float(
+        string="Cost",
+        compute="_compute_unit_cost",
+        min_display_digits="Product Price",
+        store=True,
+        readonly=False,
+        copy=False,
+    )
+    cost_ratio = fields.Float(
+        string="Cost Ratio (%)",
+        inverse="_inverse_cost_ratio",
+        store=True,
+        copy=False,
+    )
+    price_unit = fields.Float(
+        string="Sale Price",
+        compute="_compute_price_unit",
+        inverse="_inverse_price_unit",
+        store=True,
+        min_display_digits="Product Price",
+        readonly=False,
+    )
+    margin = fields.Float(
+        compute="_compute_margin",
+        min_display_digits="Product Price",
+        store=True,
+    )
+    margin_percent = fields.Float(
+        string="Margin (%)",
+        compute="_compute_margin",
+        store=True,
+    )
+    discount = fields.Float(
+        string="Disc.%",
+        digits="Discount",
+    )
+    discount_fixed = fields.Float(
+        string="Discount (Fixed)",
+        digits="Product Price",
+        help="Fixed amount discount.",
+    )
+    price_subtotal = fields.Monetary(
+        string="Amount",
+        compute="_compute_price_subtotal",
+        store=True,
+    )
+    cost_subtotal = fields.Monetary(
+        string="Cost Amount",
+        compute="_compute_cost_subtotal",
+        store=True,
+    )
+    tax_id = fields.Many2many(
+        comodel_name="account.tax", string="Taxes", check_company=True
+    )
+    company_id = fields.Many2one(
+        related="estimation_id.company_id",
+        store=True,
+    )
+    currency_id = fields.Many2one(
+        related="estimation_id.currency_id",
+    )
+
+    @api.depends("product_id", "company_id", "currency_id", "product_uom_id")
+    def _compute_unit_cost(self):
+        for line in self:
+            if not line.product_id:
+                line.unit_cost = 0.0
+                continue
+            line = line.with_company(line.company_id)
+
+            # Convert the cost to the line UoM
+            product_cost = line.product_id.uom_id._compute_price(
+                line.product_id.standard_price,
+                line.product_uom_id,
+            )
+            line.unit_cost = product_cost
+
+    def _inverse_cost_ratio(self):
+        for rec in self:
+            if rec.cost_ratio:
+                rec.price_unit = rec.unit_cost / rec.cost_ratio
+
+    @api.depends("product_id", "company_id", "currency_id", "product_uom_id")
+    def _compute_price_unit(self):
+        for line in self:
+            if not line.product_id:
+                line.price_unit = 0.0
+                continue
+            line = line.with_company(line.company_id)
+
+            # Convert the price to the line UoM
+            product_price = line.product_id.uom_id._compute_price(
+                line.product_id.list_price,
+                line.product_uom_id,
+            )
+            line.price_unit = product_price
+
+    def _inverse_price_unit(self):
+        for rec in self:
+            if rec.price_unit <= 0:
+                rec.cost_ratio = 0.0
+            else:
+                rec.cost_ratio = rec.unit_cost / rec.price_unit
+
+    @api.depends(
+        "product_uom_qty", "discount", "discount_fixed", "price_unit", "tax_id"
+    )
+    def _compute_price_subtotal(self):
+        for line in self:
+            base_line = line._prepare_base_line_for_taxes_computation()
+            self.env["account.tax"]._add_tax_details_in_base_line(
+                base_line, line.company_id
+            )
+            line.price_subtotal = base_line["tax_details"][
+                "raw_total_excluded_currency"
+            ]
+
+    @api.depends("product_uom_qty", "unit_cost")
+    def _compute_cost_subtotal(self):
+        for line in self:
+            line.cost_subtotal = line.product_uom_qty * line.unit_cost
+
+    @api.depends("price_subtotal", "product_uom_qty", "unit_cost")
+    def _compute_margin(self):
+        for line in self:
+            line.margin = line.price_subtotal - (line.unit_cost * line.product_uom_qty)
+            line.margin_percent = (
+                line.price_subtotal and line.margin / line.price_subtotal
+            )
+
+    @api.onchange("discount_fixed")
+    def _onchange_discount_fixed(self):
+        for line in self:
+            if line.discount_fixed:
+                line.discount = 0.0
+
+    @api.onchange("discount")
+    def _onchange_discount(self):
+        for line in self:
+            if line.discount:
+                line.discount_fixed = 0.0
+
+    def _get_discount_from_fixed_discount(self):
+        """Calculate the discount percentage from the fixed discount amount."""
+        self.ensure_one()
+        if not self.discount_fixed:
+            return self.discount
+
+        return (
+            (self.price_unit != 0)
+            and ((self.discount_fixed) / self.price_unit) * 100
+            or 0.00
+        )
+
+    def _prepare_base_line_for_taxes_computation(self, **kwargs):
+        """Convert the current record to a dictionary in order to use the
+        generic taxes computation method defined on account.tax.
+
+        :return: A python dictionary.
+        """
+        self.ensure_one()
+        return self.env["account.tax"]._prepare_base_line_for_taxes_computation(
+            self,
+            **{
+                "tax_ids": self.tax_id,
+                "quantity": self.product_uom_qty,
+                "partner_id": self.estimation_id.partner_id,
+                "currency_id": self.estimation_id.currency_id
+                or self.estimation_id.company_id.currency_id,
+                # 'rate': self.estimation_id.currency_rate,
+                "discount": self._get_discount_from_fixed_discount(),
+                **kwargs,
+            },
+        )
+
+    @api.depends("product_id")
+    def _compute_name(self):
+        for line in self:
+            if not line.product_id:
+                continue
+            line.name = (
+                line.product_id.get_product_multiline_description_sale()
+                or line.product_id.name
+            )
diff --git a/project_estimation/models/res_config_settings.py b/project_estimation/models/res_config_settings.py
new file mode 100644
index 0000000000..498816b4a9
--- /dev/null
+++ b/project_estimation/models/res_config_settings.py
@@ -0,0 +1,12 @@
+# Copyright 2026 Ecosoft Co., Ltd (https://ecosoft.co.th)
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+
+from odoo import fields, models
+
+
+class ResConfigSettings(models.TransientModel):
+    _inherit = "res.config.settings"
+
+    group_discount_project_estimation = fields.Boolean(
+        implied_group="project_estimation.group_discount_project_estimation"
+    )
diff --git a/project_estimation/models/sale_order.py b/project_estimation/models/sale_order.py
new file mode 100644
index 0000000000..962c55857d
--- /dev/null
+++ b/project_estimation/models/sale_order.py
@@ -0,0 +1,22 @@
+# Copyright 2026 Ecosoft Co., Ltd (https://ecosoft.co.th/)
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl.html).
+
+from odoo import fields, models
+
+
+class SaleOrder(models.Model):
+    _inherit = "sale.order"
+
+    project_estimation_id = fields.Many2one(
+        comodel_name="project.estimation",
+    )
+
+    def action_view_estimation(self):
+        self.ensure_one()
+        return {
+            "name": self.env._("Project Estimation"),
+            "type": "ir.actions.act_window",
+            "res_model": "project.estimation",
+            "view_mode": "form",
+            "res_id": self.project_estimation_id.id,
+        }
diff --git a/project_estimation/pyproject.toml b/project_estimation/pyproject.toml
new file mode 100644
index 0000000000..4231d0cccb
--- /dev/null
+++ b/project_estimation/pyproject.toml
@@ -0,0 +1,3 @@
+[build-system]
+requires = ["whool"]
+build-backend = "whool.buildapi"
diff --git a/project_estimation/readme/CONTRIBUTORS.md b/project_estimation/readme/CONTRIBUTORS.md
new file mode 100644
index 0000000000..9190ef2406
--- /dev/null
+++ b/project_estimation/readme/CONTRIBUTORS.md
@@ -0,0 +1,2 @@
+- [Ecosoft](https://ecosoft.co.th):
+  - Saran Lim. <saranl@ecosoft.co.th>
diff --git a/project_estimation/readme/DESCRIPTION.md b/project_estimation/readme/DESCRIPTION.md
new file mode 100644
index 0000000000..f9be569f3b
--- /dev/null
+++ b/project_estimation/readme/DESCRIPTION.md
@@ -0,0 +1,13 @@
+This module is a pre-sales module designed to manage project cost estimation before confirming a Sales Order.
+
+In many service-based businesses, project discussions start with rough calculations, scope alignment, and internal margin validation. Creating a full Project too early can mix pre-sales assumptions with confirmed execution data. This module separates the estimation phase from the execution phase.
+
+The purpose of this module is to:
+- Provide a structured space for cost calculation before commitment
+- Allow internal validation of pricing and margin
+- Prevent pollution of confirmed Project data with unvalidated assumptions
+- Enable clean conversion to Sales Order once approved
+
+This module represents the commercial negotiation stage, not the operational delivery stage.
+
+Once the estimation is validated and approved, it can be converted into a Sales Order. If the deal does not proceed, the estimation can simply be cancelled without impacting project reporting.
diff --git a/project_estimation/readme/USAGE.md b/project_estimation/readme/USAGE.md
new file mode 100644
index 0000000000..3a357168c1
--- /dev/null
+++ b/project_estimation/readme/USAGE.md
@@ -0,0 +1,9 @@
+To use this module, you need to:
+
+1. Go to menu Project > Estimation
+2. Create a new Project Estimation
+3. Add estimation lines such as services, materials, or working hours. For each line, define quantity, cost, and price.
+4. Review the overall estimation. Adjust pricing or quantities until the expected margin meets business requirements.
+5. Once internally validated, confirm the estimation.
+6. Click Create Sales Order. It will generate a Sales Order based on the estimation lines, and the standard sales workflow continues from there.
+7. If the deal does not proceed, simply cancel the estimation. No Project or accounting records will be affected.
diff --git a/project_estimation/security/ir.model.access.csv b/project_estimation/security/ir.model.access.csv
new file mode 100644
index 0000000000..3659b76085
--- /dev/null
+++ b/project_estimation/security/ir.model.access.csv
@@ -0,0 +1,5 @@
+id,name,model_id:id,group_id:id,perm_read,perm_write,perm_create,perm_unlink
+access_project_estimation_user,access_project_estimation_user,model_project_estimation,project.group_project_user,1,1,1,1
+access_project_estimation_line_user,access_project_estimation_line_user,model_project_estimation_line,project.group_project_user,1,1,1,1
+access_project_estimation_create_sale_order,access_project_estimation_create_sale_order,model_project_estimation_create_sale_order,project.group_project_user,1,1,1,1
+access_project_estimation_create_sale_order_line,access_project_estimation_create_sale_order_line,model_project_estimation_create_sale_order_line,project.group_project_user,1,1,1,1
diff --git a/project_estimation/security/project_estimation_security.xml b/project_estimation/security/project_estimation_security.xml
new file mode 100644
index 0000000000..2d04b2ae22
--- /dev/null
+++ b/project_estimation/security/project_estimation_security.xml
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<odoo>
+    <record id="project_estimation_rule" model="ir.rule">
+        <field name="name">Project Estimation multi company rule</field>
+        <field name="model_id" ref="model_project_estimation" />
+        <field name="global" eval="True" />
+        <field
+            name="domain_force"
+        >['|',('company_id','=',False),('company_id', 'in', company_ids)]</field>
+    </record>
+</odoo>
diff --git a/project_estimation/security/res_groups.xml b/project_estimation/security/res_groups.xml
new file mode 100644
index 0000000000..ce464cdf77
--- /dev/null
+++ b/project_estimation/security/res_groups.xml
@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<odoo>
+    <record id="group_discount_project_estimation" model="res.groups">
+        <field name="name">Discount on Project Estimation</field>
+        <field name="category_id" ref="base.module_category_hidden" />
+    </record>
+</odoo>
diff --git a/project_estimation/static/description/index.html b/project_estimation/static/description/index.html
new file mode 100644
index 0000000000..85f575dfb5
--- /dev/null
+++ b/project_estimation/static/description/index.html
@@ -0,0 +1,472 @@
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+<head>
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+<meta name="generator" content="Docutils: https://docutils.sourceforge.io/" />
+<title>Project Estimation</title>
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+
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+<body>
+<div class="document" id="project-estimation">
+<h1 class="title">Project Estimation</h1>
+
+<!-- !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+!! This file is generated by oca-gen-addon-readme !!
+!! changes will be overwritten.                   !!
+!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+!! source digest: sha256:0faffaf36b0c57e81ee69946cb1d5445d5dae4f3efa82e3e0219d5f7a1fec03e
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+<p><a class="reference external image-reference" href="https://odoo-community.org/page/development-status"><img alt="Alpha" src="https://img.shields.io/badge/maturity-Alpha-red.png" /></a> <a class="reference external image-reference" href="http://www.gnu.org/licenses/agpl-3.0-standalone.html"><img alt="License: AGPL-3" src="https://img.shields.io/badge/licence-AGPL--3-blue.png" /></a> <a class="reference external image-reference" href="https://github.com/OCA/project/tree/18.0/project_estimation"><img alt="OCA/project" src="https://img.shields.io/badge/github-OCA%2Fproject-lightgray.png?logo=github" /></a> <a class="reference external image-reference" href="https://translation.odoo-community.org/projects/project-18-0/project-18-0-project_estimation"><img alt="Translate me on Weblate" src="https://img.shields.io/badge/weblate-Translate%20me-F47D42.png" /></a> <a class="reference external image-reference" href="https://runboat.odoo-community.org/builds?repo=OCA/project&amp;target_branch=18.0"><img alt="Try me on Runboat" src="https://img.shields.io/badge/runboat-Try%20me-875A7B.png" /></a></p>
+<p>This module is a pre-sales module designed to manage project cost
+estimation before confirming a Sales Order.</p>
+<p>In many service-based businesses, project discussions start with rough
+calculations, scope alignment, and internal margin validation. Creating
+a full Project too early can mix pre-sales assumptions with confirmed
+execution data. This module separates the estimation phase from the
+execution phase.</p>
+<p>The purpose of this module is to:</p>
+<ul class="simple">
+<li>Provide a structured space for cost calculation before commitment</li>
+<li>Allow internal validation of pricing and margin</li>
+<li>Prevent pollution of confirmed Project data with unvalidated
+assumptions</li>
+<li>Enable clean conversion to Sales Order once approved</li>
+</ul>
+<p>This module represents the commercial negotiation stage, not the
+operational delivery stage.</p>
+<p>Once the estimation is validated and approved, it can be converted into
+a Sales Order. If the deal does not proceed, the estimation can simply
+be cancelled without impacting project reporting.</p>
+<div class="admonition important">
+<p class="first admonition-title">Important</p>
+<p class="last">This is an alpha version, the data model and design can change at any time without warning.
+Only for development or testing purpose, do not use in production.
+<a class="reference external" href="https://odoo-community.org/page/development-status">More details on development status</a></p>
+</div>
+<p><strong>Table of contents</strong></p>
+<div class="contents local topic" id="contents">
+<ul class="simple">
+<li><a class="reference internal" href="#usage" id="toc-entry-1">Usage</a></li>
+<li><a class="reference internal" href="#bug-tracker" id="toc-entry-2">Bug Tracker</a></li>
+<li><a class="reference internal" href="#credits" id="toc-entry-3">Credits</a><ul>
+<li><a class="reference internal" href="#authors" id="toc-entry-4">Authors</a></li>
+<li><a class="reference internal" href="#contributors" id="toc-entry-5">Contributors</a></li>
+<li><a class="reference internal" href="#maintainers" id="toc-entry-6">Maintainers</a></li>
+</ul>
+</li>
+</ul>
+</div>
+<div class="section" id="usage">
+<h1><a class="toc-backref" href="#toc-entry-1">Usage</a></h1>
+<p>To use this module, you need to:</p>
+<ol class="arabic simple">
+<li>Go to menu Project &gt; Estimation</li>
+<li>Create a new Project Estimation</li>
+<li>Add estimation lines such as services, materials, or working hours.
+For each line, define quantity, cost, and price.</li>
+<li>Review the overall estimation. Adjust pricing or quantities until the
+expected margin meets business requirements.</li>
+<li>Once internally validated, confirm the estimation.</li>
+<li>Click Create Sales Order. It will generate a Sales Order based on the
+estimation lines, and the standard sales workflow continues from
+there.</li>
+<li>If the deal does not proceed, simply cancel the estimation. No
+Project or accounting records will be affected.</li>
+</ol>
+</div>
+<div class="section" id="bug-tracker">
+<h1><a class="toc-backref" href="#toc-entry-2">Bug Tracker</a></h1>
+<p>Bugs are tracked on <a class="reference external" href="https://github.com/OCA/project/issues">GitHub Issues</a>.
+In case of trouble, please check there if your issue has already been reported.
+If you spotted it first, help us to smash it by providing a detailed and welcomed
+<a class="reference external" href="https://github.com/OCA/project/issues/new?body=module:%20project_estimation%0Aversion:%2018.0%0A%0A**Steps%20to%20reproduce**%0A-%20...%0A%0A**Current%20behavior**%0A%0A**Expected%20behavior**">feedback</a>.</p>
+<p>Do not contact contributors directly about support or help with technical issues.</p>
+</div>
+<div class="section" id="credits">
+<h1><a class="toc-backref" href="#toc-entry-3">Credits</a></h1>
+<div class="section" id="authors">
+<h2><a class="toc-backref" href="#toc-entry-4">Authors</a></h2>
+<ul class="simple">
+<li>Ecosoft</li>
+</ul>
+</div>
+<div class="section" id="contributors">
+<h2><a class="toc-backref" href="#toc-entry-5">Contributors</a></h2>
+<ul class="simple">
+<li><a class="reference external" href="https://ecosoft.co.th">Ecosoft</a>:<ul>
+<li>Saran Lim. <a class="reference external" href="mailto:saranl&#64;ecosoft.co.th">saranl&#64;ecosoft.co.th</a></li>
+</ul>
+</li>
+</ul>
+</div>
+<div class="section" id="maintainers">
+<h2><a class="toc-backref" href="#toc-entry-6">Maintainers</a></h2>
+<p>This module is maintained by the OCA.</p>
+<a class="reference external image-reference" href="https://odoo-community.org">
+<img alt="Odoo Community Association" src="https://odoo-community.org/logo.png" />
+</a>
+<p>OCA, or the Odoo Community Association, is a nonprofit organization whose
+mission is to support the collaborative development of Odoo features and
+promote its widespread use.</p>
+<p>Current <a class="reference external" href="https://odoo-community.org/page/maintainer-role">maintainer</a>:</p>
+<p><a class="reference external image-reference" href="https://github.com/Saran440"><img alt="Saran440" src="https://github.com/Saran440.png?size=40px" /></a></p>
+<p>This module is part of the <a class="reference external" href="https://github.com/OCA/project/tree/18.0/project_estimation">OCA/project</a> project on GitHub.</p>
+<p>You are welcome to contribute. To learn how please visit <a class="reference external" href="https://odoo-community.org/page/Contribute">https://odoo-community.org/page/Contribute</a>.</p>
+</div>
+</div>
+</div>
+</body>
+</html>
diff --git a/project_estimation/tests/__init__.py b/project_estimation/tests/__init__.py
new file mode 100644
index 0000000000..c4d1a4baff
--- /dev/null
+++ b/project_estimation/tests/__init__.py
@@ -0,0 +1,3 @@
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+
+from . import test_project_estimation
diff --git a/project_estimation/tests/test_project_estimation.py b/project_estimation/tests/test_project_estimation.py
new file mode 100644
index 0000000000..4230005111
--- /dev/null
+++ b/project_estimation/tests/test_project_estimation.py
@@ -0,0 +1,168 @@
+# Copyright 2026 Ecosoft Co., Ltd (https://ecosoft.co.th)
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+
+from odoo import Command
+from odoo.tests.common import TransactionCase
+
+
+class TestProjectEstimation(TransactionCase):
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        cls.env = cls.env(context=dict(cls.env.context, tracking_disable=True))
+
+        cls.company = cls.env.company
+        cls.partner = cls.env["res.partner"].create({"name": "Test Customer"})
+        cls.uom_unit = cls.env.ref("uom.product_uom_unit")
+
+        cls.tax_7 = cls.env["account.tax"].create(
+            {
+                "name": "Tax 7%",
+                "amount_type": "percent",
+                "amount": 7.0,
+                "type_tax_use": "sale",
+            }
+        )
+
+        # Product
+        cls.product = cls.env["product.product"].create(
+            {
+                "name": "Test Service",
+                "type": "service",
+                "uom_id": cls.uom_unit.id,
+                "uom_po_id": cls.uom_unit.id,
+                "standard_price": 50.0,
+                "list_price": 100.0,
+            }
+        )
+
+    def test_01_estimation_computations(self):
+        """Test subtotal, margin, and total computations on estimation."""
+        estimation = self.env["project.estimation"].create(
+            {
+                "partner_id": self.partner.id,
+                "target_margin": 20.0,
+                "line_ids": [
+                    Command.create(
+                        {
+                            "product_id": self.product.id,
+                            "name": self.product.name,
+                            "product_uom_qty": 2.0,
+                            "price_unit": 100.0,
+                            "unit_cost": 50.0,
+                            "tax_id": [Command.set(self.tax_7.ids)],
+                        }
+                    )
+                ],
+            }
+        )
+
+        line = estimation.line_ids[0]
+
+        self.assertEqual(line.price_subtotal, 200.0)  # 2 * 100
+        self.assertEqual(line.cost_subtotal, 100.0)  # 2 * 50
+        self.assertEqual(line.margin, 100.0)  # 200 - 100
+        self.assertEqual(line.margin_percent, 0.5)  # 100 / 200 = 50%
+
+        self.assertEqual(estimation.total_cost, 100.0)
+        self.assertEqual(estimation.amount_untaxed, 200.0)
+        self.assertEqual(estimation.amount_tax, 14.0)  # 200 * 0.07
+        self.assertEqual(estimation.amount_total, 214.0)
+
+        self.assertEqual(estimation.total_margin, 100.0)
+        self.assertEqual(estimation.total_margin_percent, 0.5)
+
+        # Target expected fields
+        # total_cost / (1 - target_margin) -> 100 / (1 - 0.2) = 125
+        self.assertEqual(estimation.target_sale_price, 125.0)
+        self.assertEqual(estimation.expected_profit, 25.0)
+
+    def test_02_workflow_and_wizard(self):
+        """Test estimation workflow and wizard Sale Order generation."""
+        estimation = self.env["project.estimation"].create(
+            {
+                "partner_id": self.partner.id,
+                "line_ids": [
+                    Command.create(
+                        {
+                            "product_id": self.product.id,
+                            "name": self.product.name,
+                            "product_uom_qty": 1.0,
+                            "price_unit": 100.0,
+                            "unit_cost": 50.0,
+                        }
+                    )
+                ],
+            }
+        )
+
+        self.assertEqual(estimation.state, "draft")
+        estimation.action_approve()
+        self.assertEqual(estimation.state, "approved")
+
+        # Open Wizard
+        wizard = (
+            self.env["project.estimation.create.sale.order"]
+            .with_context(default_estimation_id=estimation.id)
+            .create(
+                {
+                    "estimation_id": estimation.id,
+                }
+            )
+        )
+
+        # Ensure wizard loaded lines properly
+        self.assertEqual(len(wizard.line_ids), 1)
+        self.assertEqual(wizard.line_ids[0].price_unit, 100.0)
+
+        # Execute wizard
+        res = wizard.action_create_sale_order()
+
+        # Check wizard result
+        self.assertEqual(res["res_model"], "sale.order")
+        self.assertEqual(estimation.state, "won")
+
+        so = self.env["sale.order"].browse(res["res_id"])
+        self.assertEqual(so.partner_id, self.partner)
+        self.assertEqual(len(so.order_line), 1)
+        self.assertEqual(so.order_line[0].price_unit, 100.0)
+
+        # Ensure project was created as requested
+        self.assertTrue(estimation.project_id)
+        self.assertEqual(estimation.project_id.name, estimation.name)
+
+    def test_03_display_type_no_computations(self):
+        """Test section/note lines and ensure they don't break computation."""
+        estimation = self.env["project.estimation"].create(
+            {
+                "partner_id": self.partner.id,
+                "line_ids": [
+                    Command.create(
+                        {
+                            "display_type": "line_section",
+                            "name": "Section A",
+                        }
+                    ),
+                    Command.create(
+                        {
+                            "product_id": self.product.id,
+                            "name": self.product.name,
+                            "product_uom_qty": 1.0,
+                            "price_unit": 100.0,
+                            "unit_cost": 50.0,
+                        }
+                    ),
+                ],
+            }
+        )
+
+        section_line = estimation.line_ids.filtered(
+            lambda line: line.display_type == "line_section"
+        )
+        self.assertTrue(section_line)
+        self.assertEqual(section_line.cost_subtotal, 0.0)
+        self.assertEqual(section_line.price_subtotal, 0.0)
+
+        # Totals should ignore section line
+        self.assertEqual(estimation.total_cost, 50.0)
+        self.assertEqual(estimation.amount_untaxed, 100.0)
diff --git a/project_estimation/views/project_estimation_views.xml b/project_estimation/views/project_estimation_views.xml
new file mode 100644
index 0000000000..da778e2559
--- /dev/null
+++ b/project_estimation/views/project_estimation_views.xml
@@ -0,0 +1,366 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<odoo>
+    <!-- List View -->
+    <record id="view_project_estimation_list" model="ir.ui.view">
+        <field name="name">project.estimation.list</field>
+        <field name="model">project.estimation</field>
+        <field name="arch" type="xml">
+            <list>
+                <field name="name" />
+                <field name="partner_id" />
+                <field name="date" />
+                <field name="user_id" widget="many2one_avatar_user" optional="show" />
+                <field
+                    name="company_id"
+                    groups="base.group_multi_company"
+                    optional="show"
+                />
+                <field name="currency_id" column_invisible="1" />
+                <field name="total_cost" />
+                <field name="target_margin" optional="show" />
+                <field name="target_sale_price" />
+                <field name="expected_profit" optional="show" />
+                <field
+                    name="state"
+                    widget="badge"
+                    decoration-info="state == 'draft'"
+                    decoration-success="state in ('confirm', 'approved', 'done')"
+                    decoration-danger="state == 'cancelled'"
+                />
+            </list>
+        </field>
+    </record>
+
+    <!-- Form View -->
+    <record id="view_project_estimation_form" model="ir.ui.view">
+        <field name="name">project.estimation.form</field>
+        <field name="model">project.estimation</field>
+        <field name="arch" type="xml">
+            <form>
+                <header>
+                    <button
+                        name="action_confirm"
+                        string="Confirm"
+                        type="object"
+                        class="oe_highlight"
+                        invisible="state != 'draft'"
+                    />
+                    <button
+                        name="action_approve"
+                        string="Approve"
+                        type="object"
+                        class="oe_highlight"
+                        invisible="state != 'confirm'"
+                    />
+                    <button
+                        id="action_create_sale_order_button_highlight"
+                        name="action_create_sale_order"
+                        string="Create Sale Order"
+                        type="object"
+                        class="oe_highlight"
+                        invisible="state != 'approved' or sale_order_ids"
+                    />
+                    <button
+                        id="action_create_sale_order_button"
+                        name="action_create_sale_order"
+                        string="Create Sale Order"
+                        type="object"
+                        invisible="state != 'approved' or not sale_order_ids"
+                    />
+                    <button
+                        id="action_done_button_highlight"
+                        name="action_done"
+                        string="Done"
+                        type="object"
+                        class="oe_highlight"
+                        invisible="state != 'approved' or not sale_order_ids"
+                        confirm="Are you sure you want to mark this estimation as done?"
+                    />
+                    <button
+                        id="action_done_button"
+                        name="action_done"
+                        string="Done"
+                        type="object"
+                        invisible="state != 'approved' or sale_order_ids"
+                        confirm="Are you sure you want to mark this estimation as done?"
+                    />
+                    <button
+                        name="action_cancel"
+                        string="Cancel"
+                        type="object"
+                        invisible="state not in ('draft', 'approved')"
+                    />
+                    <button
+                        name="action_draft"
+                        string="Reset to Draft"
+                        type="object"
+                        invisible="state not in ('confirm', 'approved', 'cancelled')"
+                    />
+                    <field
+                        name="state"
+                        widget="statusbar"
+                        statusbar_visible="draft,confirm,approved,done"
+                    />
+                </header>
+                <sheet>
+                    <div class="oe_button_box" name="button_box">
+                        <button
+                            name="action_view_sale_order"
+                            type="object"
+                            class="oe_stat_button"
+                            icon="fa-pencil-square-o"
+                            invisible="not sale_order_ids"
+                        >
+                            <field
+                                name="sale_order_ids"
+                                widget="statinfo"
+                                string="Sale Order"
+                            />
+                        </button>
+                        <button
+                            name="action_view_project"
+                            type="object"
+                            class="oe_stat_button"
+                            icon="fa-puzzle-piece"
+                            invisible="not project_id"
+                        >
+                            <field
+                                name="project_id"
+                                widget="statinfo"
+                                string="Project"
+                            />
+                        </button>
+                    </div>
+                    <div class="oe_title">
+                        <label for="name" class="oe_edit_only" />
+                        <h1>
+                            <field name="name" readonly="1" />
+                        </h1>
+                    </div>
+                    <group name="main_info">
+                        <group>
+                            <field name="partner_id" readonly="state != 'draft'" />
+                            <field
+                                name="user_id"
+                                widget="many2one_avatar_user"
+                                readonly="state != 'draft'"
+                            />
+                        </group>
+                        <group>
+                            <field
+                                name="company_id"
+                                groups="base.group_multi_company"
+                            />
+                            <field name="currency_id" invisible="1" />
+                            <field
+                                name="currency_id"
+                                groups="base.group_multi_currency"
+                                readonly="state != 'draft'"
+                            />
+                            <field name="date" readonly="state != 'draft'" />
+                        </group>
+                    </group>
+                    <group name="target" string="Target">
+                        <group>
+                            <field name="target_margin" readonly="state != 'draft'" />
+                        </group>
+                        <group>
+                            <field name="target_sale_price" />
+                            <field name="expected_profit" />
+                        </group>
+                    </group>
+                    <notebook>
+                        <page string="Estimation Lines" name="lines">
+                            <field
+                                name="line_ids"
+                                widget="section_and_note_one2many"
+                                readonly="state != 'draft'"
+                            >
+                                <list editable="bottom">
+                                    <control>
+                                        <create
+                                            name="add_line_control"
+                                            string="Add a line"
+                                        />
+                                        <create
+                                            name="add_section_control"
+                                            string="Add a section"
+                                            context="{'default_display_type': 'line_section'}"
+                                        />
+                                        <create
+                                            name="add_note_control"
+                                            string="Add a note"
+                                            context="{'default_display_type': 'line_note'}"
+                                        />
+                                    </control>
+                                    <field name="display_type" column_invisible="1" />
+                                    <field name="sequence" widget="handle" />
+                                    <field name="product_id" />
+                                    <field name="name" widget="section_and_note_text" />
+                                    <field name="cost_type" optional="show" />
+                                    <field name="product_uom_qty" />
+                                    <field
+                                        name="product_uom_id"
+                                        groups="uom.group_uom"
+                                        optional="show"
+                                    />
+                                    <field name="currency_id" column_invisible="1" />
+                                    <field name="unit_cost" />
+                                    <field
+                                        name="cost_ratio"
+                                        optional="show"
+                                        widget="percentage"
+                                    />
+                                    <field name="price_unit" />
+                                    <field name="margin" optional="show" />
+                                    <field
+                                        name="margin_percent"
+                                        optional="show"
+                                        widget="percentage"
+                                    />
+                                    <field
+                                        name="tax_id"
+                                        widget="many2many_tags"
+                                        options="{'no_create': True}"
+                                        context="{'search_view_ref': 'account.account_tax_view_search'}"
+                                        optional="show"
+                                        domain="[('type_tax_use', '=', 'sale'), ('company_id', '=', company_id)]"
+                                    />
+                                    <field
+                                        name="discount_fixed"
+                                        optional="show"
+                                        groups="project_estimation.group_discount_project_estimation"
+                                    />
+                                    <field
+                                        name="discount"
+                                        optional="show"
+                                        groups="project_estimation.group_discount_project_estimation"
+                                    />
+                                    <field name="cost_subtotal" optional="hide" />
+                                    <field name="price_subtotal" />
+                                </list>
+                            </field>
+                            <group col="12">
+                                <group colspan="8">
+                                    <field
+                                        name="note"
+                                        placeholder="Notes..."
+                                        nolabel="1"
+                                    />
+                                </group>
+                                <group colspan="4">
+                                    <group
+                                        name="cost_summary"
+                                        class="oe_subtotal_footer"
+                                    >
+                                        <field name="total_cost" />
+                                    </group>
+                                    <group
+                                        name="sale_summary"
+                                        class="oe_subtotal_footer"
+                                    >
+                                        <field name="amount_untaxed" />
+                                        <field name="amount_tax" />
+                                        <div
+                                            class="oe_subtotal_footer_separator oe_inline"
+                                        >
+                                            <label for="amount_total" />
+                                        </div>
+                                        <field
+                                            name="amount_total"
+                                            nolabel="1"
+                                            class="oe_subtotal_footer_separator"
+                                        />
+                                        <div class="d-flex float-end" colspan="2">
+                                            <label for="total_margin" />
+                                            <div>
+                                                <field
+                                                    name="total_margin"
+                                                    class="oe_inline"
+                                                />
+                                                <span class="oe_inline">
+                                                    (<field
+                                                    name="total_margin_percent"
+                                                    nolabel="1"
+                                                    class="oe_inline"
+                                                    widget="percentage"
+                                                />)
+                                                </span>
+                                            </div>
+                                        </div>
+                                    </group>
+                                </group>
+                            </group>
+                        </page>
+                    </notebook>
+                </sheet>
+                <chatter />
+            </form>
+        </field>
+    </record>
+
+    <record id="view_project_estimation_search" model="ir.ui.view">
+        <field name="name">project.estimation.search</field>
+        <field name="model">project.estimation</field>
+        <field name="arch" type="xml">
+            <search>
+                <field name="name" />
+                <field name="partner_id" />
+                <field name="date" />
+                <separator />
+                <group string="Group By">
+                    <filter
+                        name="groupby_company"
+                        string="Company"
+                        context="{'group_by':'company_id'}"
+                        groups="base.group_multi_company"
+                    />
+                    <filter
+                        name="groupby_currency"
+                        string="Currency"
+                        context="{'group_by':'currency_id'}"
+                        groups="base.group_multi_currency"
+                    />
+                    <filter
+                        name="groupby_state"
+                        string="Status"
+                        context="{'group_by':'state'}"
+                    />
+                    <separator />
+                    <filter
+                        name="groupby_partner"
+                        string="Partner"
+                        context="{'group_by':'partner_id'}"
+                    />
+                    <filter
+                        name="groupby_user_id"
+                        string="Responsible"
+                        context="{'group_by':'user_id'}"
+                    />
+                </group>
+            </search>
+        </field>
+    </record>
+
+    <!-- Action -->
+    <record id="action_project_estimation" model="ir.actions.act_window">
+        <field name="name">Estimations</field>
+        <field name="res_model">project.estimation</field>
+        <field name="view_mode">list,form</field>
+    </record>
+
+    <!-- Menu Items -->
+    <menuitem
+        id="menu_main_project_estimation"
+        name="Estimation"
+        parent="project.menu_main_pm"
+        sequence="30"
+    />
+    <menuitem
+        id="menu_project_estimation"
+        name="Estimations"
+        parent="menu_main_project_estimation"
+        action="action_project_estimation"
+        sequence="10"
+    />
+</odoo>
diff --git a/project_estimation/views/res_config_settings_views.xml b/project_estimation/views/res_config_settings_views.xml
new file mode 100644
index 0000000000..e276b02a7a
--- /dev/null
+++ b/project_estimation/views/res_config_settings_views.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<odoo>
+    <record id="res_config_settings_view_form" model="ir.ui.view">
+        <field name="name">Configure project display name</field>
+        <field name="model">res.config.settings</field>
+        <field name="inherit_id" ref="project.res_config_settings_view_form" />
+        <field name="arch" type="xml">
+            <xpath expr="//app[@name='project']" position="inside">
+                <block title="Project Estimation" name="project_estimation">
+                    <setting
+                        id="discount_project_estimation_lines"
+                        title="Apply manual discounts on project estimation lines"
+                        help="Grant discounts on project estimation lines"
+                    >
+                        <field
+                            name="group_discount_project_estimation"
+                            string="Discounts"
+                        />
+                    </setting>
+                </block>
+            </xpath>
+        </field>
+    </record>
+</odoo>
diff --git a/project_estimation/views/sale_order_view.xml b/project_estimation/views/sale_order_view.xml
new file mode 100644
index 0000000000..345ab76142
--- /dev/null
+++ b/project_estimation/views/sale_order_view.xml
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<odoo>
+    <record id="view_order_form" model="ir.ui.view">
+        <field name="name">sale.order.form</field>
+        <field name="model">sale.order</field>
+        <field name="inherit_id" ref="sale.view_order_form" />
+        <field name="arch" type="xml">
+            <xpath expr="//group[@name='sale_reporting']" position="inside">
+                <field name="project_estimation_id" readonly="1" />
+            </xpath>
+        </field>
+    </record>
+</odoo>
diff --git a/project_estimation/wizard/__init__.py b/project_estimation/wizard/__init__.py
new file mode 100644
index 0000000000..4497c268f9
--- /dev/null
+++ b/project_estimation/wizard/__init__.py
@@ -0,0 +1,3 @@
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+
+from . import create_sale_order
diff --git a/project_estimation/wizard/create_sale_order.py b/project_estimation/wizard/create_sale_order.py
new file mode 100644
index 0000000000..43329be018
--- /dev/null
+++ b/project_estimation/wizard/create_sale_order.py
@@ -0,0 +1,118 @@
+# Copyright 2026 Ecosoft Co., Ltd (https://ecosoft.co.th)
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+
+from odoo import Command, _, api, fields, models
+from odoo.exceptions import UserError
+
+
+class ProjectEstimationCreateSaleOrder(models.TransientModel):
+    _name = "project.estimation.create.sale.order"
+    _description = "Create Sale Order from Estimation"
+
+    estimation_id = fields.Many2one(
+        comodel_name="project.estimation",
+        required=True,
+        readonly=True,
+    )
+    partner_id = fields.Many2one(
+        related="estimation_id.partner_id",
+    )
+    line_ids = fields.One2many(
+        comodel_name="project.estimation.create.sale.order.line",
+        inverse_name="wizard_id",
+        string="Sale Order Lines",
+    )
+
+    def _get_data_lines(self, line):
+        return {
+            "display_type": line.display_type,
+            "product_id": line.product_id.id,
+            "name": line.name,
+            "product_uom_qty": line.product_uom_qty,
+            "price_unit": line.price_unit,
+            "tax_id": [Command.set(line.tax_id.ids)],
+        }
+
+    def _get_sale_order_vals(self):
+        so_lines = [
+            Command.create(self._get_data_lines(line)) for line in self.line_ids
+        ]
+        so_vals = [
+            {
+                "partner_id": self.partner_id.id,
+                "origin": self.estimation_id.name,
+                "project_estimation_id": self.estimation_id.id,
+                "order_line": so_lines,
+            }
+        ]
+        return so_vals
+
+    @api.model
+    def default_get(self, fields_list):
+        res = super().default_get(fields_list)
+        estimation_id = res.get("estimation_id") or self.env.context.get(
+            "default_estimation_id"
+        )
+        if estimation_id:
+            estimation = self.env["project.estimation"].browse(estimation_id)
+            lines = [
+                Command.create(self._get_data_lines(line))
+                for line in estimation.line_ids
+            ]
+            res["line_ids"] = lines
+        return res
+
+    def action_create_sale_order(self):
+        self.ensure_one()
+        if not self.line_ids:
+            raise UserError(self.env._("No lines to create Sale Order."))
+
+        # Create Sale Order
+        so_vals = self._get_sale_order_vals()
+        sale_order = self.env["sale.order"].create(so_vals)
+
+        # Return action to view the created Sale Order
+        return {
+            "name": _("Sale Order"),
+            "type": "ir.actions.act_window",
+            "res_model": "sale.order",
+            "view_mode": "form",
+            "res_id": sale_order.id,
+        }
+
+
+class ProjectEstimationCreateSaleOrderLine(models.TransientModel):
+    _name = "project.estimation.create.sale.order.line"
+    _description = "Create Sale Order Line"
+
+    wizard_id = fields.Many2one(
+        comodel_name="project.estimation.create.sale.order",
+        required=True,
+        ondelete="cascade",
+    )
+    display_type = fields.Selection(
+        selection=[
+            ("line_section", "Section"),
+            ("line_note", "Note"),
+        ],
+        default=False,
+    )
+    product_id = fields.Many2one(
+        comodel_name="product.product",
+    )
+    name = fields.Char(string="Description")
+    product_uom_qty = fields.Float(string="Quantity", default=1.0)
+    price_unit = fields.Float(string="Unit Price")
+    tax_id = fields.Many2many(
+        comodel_name="account.tax",
+        string="Taxes",
+    )
+    price_subtotal = fields.Float(
+        string="Subtotal",
+        compute="_compute_price_subtotal",
+    )
+
+    @api.depends("product_uom_qty", "price_unit")
+    def _compute_price_subtotal(self):
+        for line in self:
+            line.price_subtotal = line.product_uom_qty * line.price_unit
diff --git a/project_estimation/wizard/create_sale_order_view.xml b/project_estimation/wizard/create_sale_order_view.xml
new file mode 100644
index 0000000000..8d5351caaf
--- /dev/null
+++ b/project_estimation/wizard/create_sale_order_view.xml
@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<odoo>
+    <record id="view_project_estimation_create_sale_order_form" model="ir.ui.view">
+        <field name="name">project.estimation.create.sale.order.form</field>
+        <field name="model">project.estimation.create.sale.order</field>
+        <field name="arch" type="xml">
+            <form string="Create Sale Order">
+                <group>
+                    <field name="estimation_id" invisible="1" />
+                    <field name="partner_id" readonly="1" />
+                </group>
+                <notebook>
+                    <page string="Sale Order Lines">
+                        <field name="line_ids" widget="section_and_note_one2many">
+                            <list editable="bottom">
+                                <field name="display_type" column_invisible="1" />
+                                <field name="product_id" optional="show" />
+                                <field name="name" widget="section_and_note_text" />
+                                <field name="product_uom_qty" />
+                                <field name="price_unit" />
+                                <field
+                                    name="tax_id"
+                                    widget="many2many_tags"
+                                    optional="show"
+                                />
+                                <field name="price_subtotal" />
+                            </list>
+                        </field>
+                    </page>
+                </notebook>
+                <footer>
+                    <button
+                        name="action_create_sale_order"
+                        string="Create Sale Order"
+                        type="object"
+                        class="btn-primary"
+                    />
+                    <button string="Cancel" special="cancel" />
+                </footer>
+            </form>
+        </field>
+    </record>
+</odoo>