Tax Fixed Amount Multiplier
This module adds a multiplier option to fixed-amount taxes, controlling how the line quantity is used in the tax computation.
By default, Odoo computes fixed taxes as line quantity × amount. This module allows choosing between four multiplier modes:
- No Multiplier: the amount is applied once per line, regardless of quantity. Useful for per-document fees (e.g., stamp duties).
- Quantity (default): standard behavior, equivalent to line quantity × amount.
- Product Quantity: the line quantity is first converted to the product's unit of measure before multiplying. This is useful when the tax is defined per unit of the product, but the line may use a different UoM (e.g., selling in dozens while the product is defined in units).
- Product Weight: multiplied by the total weight of the products on the line (product quantity × product weight). Useful for weight-based fees such as environmental levies.
This module is compatible with account_tax_fixed_amount_currency without depending on it. When both modules are installed, the selected multiplier changes the fixed-tax quantity first, and the currency module can then convert the resulting fixed amount to the document currency through the normal tax computation chain.
auto_awesome What this module does
AI-generated from the code · Odoo 19.0Adds a "Multiplier" option on fixed-amount taxes so you can choose whether the tax amount is applied once per line, per line quantity, per product unit of measure, or per product weight.
When you configure a tax of type "Fixed Amount" in Accounting, a new "Multiplier" field appears on the tax form. It lets you decide how the fixed amount is multiplied when the tax is computed on an invoice or bill line.
- No Multiplier: the fixed amount is applied once per line, whatever the quantity. Useful for per-document fees such as stamp duties.
- Quantity (default): the standard Odoo behaviour, the amount is multiplied by the line quantity.
- Product Quantity: the line quantity is first converted into the product's own unit of measure before multiplying. Handy when you sell in dozens but the product is defined in units.
- Product Weight: the amount is multiplied by the total weight of the products on the line (quantity converted to the product unit of measure, times the product weight). Useful for weight-based fees.
The setting is stored on account.tax and is used both by the server-side tax computation and by the JavaScript helper used in the web client, so the same result is shown in the interface and saved in the database. The module also exposes the product's unit-of-measure factor on product.template so the conversion can be done. No new menus or reports are added; the change is visible directly on the tax configuration screen.
Depends on
Models and fields (2)
- account.tax · extends an existing modelfixed_amount_multiplier (Multiplier)
- product.template · extends an existing modeluom_factor
Text generated by AI (DeepSeek) from reading the Odoo 19.0 code on GitHub; it may contain mistakes, so check the code before deciding. View the code on GitHub
Availability by version
Reviewed: 2026-11-03Confirmation status: 1 confirmed, 8 with no information of 9 versions.
Sources · Odoo 19.0
Confirmed on 2026-11-03 in branch 19.0 of OCA/account-invoicing.
terminal Installation and usage
OCA documentation · Odoo 19.0Configuration
Source · Odoo 19.0To configure this module, you need to:
- Go to Invoicing > Configuration > Taxes.
- Open or create a tax with Tax Computation set to Fixed.
- Set the Amount Multiplier field to the desired mode:
- No Multiplier: the tax amount is applied once per line.
- Quantity (default): standard behavior, multiplied by the line quantity regardless of the unit of measure.
- Product Quantity: the line quantity is converted to the product's unit of measure before multiplying.
- Product Weight: multiplied by the total weight (product quantity × product weight).
Usage
Source · Odoo 19.0Product Quantity mode is useful for per-unit taxes where the product may be sold in different units of measure.
For example, if a product is defined in Units and has a per-unit tax of 5.00, selling 1 Dozen will compute the tax as:
1 dozen = 12 units → tax = 12 × 5.00 = 60.00
This also works with nested UoM hierarchies. For example, selling 1 Box of 10 Dozens will compute:
1 box = 10 dozens = 120 units → tax = 120 × 5.00 = 600.00
Product Weight mode is useful for weight-based fees. For example, with a levy of 3.00 per kilogram and a product weighing 2.5 kg:
10 units × 2.5 kg/unit × 3.00/kg = 75.00
If account_tax_fixed_amount_currency is also installed, configure the fixed tax currency on the tax as usual. The multiplier changes the quantity used by the fixed tax computation, and the resulting amount is then converted by the currency module.
No verified information in OCA: Installation.
Installation instructions, the distribution package, dependencies and configuration steps are not shown because they have not yet been verified in the module documentation for any version.
Data imported from GitHub: this sheet reflects the latest catalog review, not a live lookup. Always check the module documentation and staging before installing in production.