With tax categories on, the rate comes from the product, then its product category, then your default. Set the rate at the widest level that is true, and override only the exceptions.
Set the tax of a product category
Edit a main category
Go to Catalogue › Categories and edit a main category.
Choose its tax
Under Main category settings, choose a rate in Tax. Default uses your shop's Default Tax Category.
The Tax field is shown on main categories only. A product whose own Category is a sub-category is taxed at your Default Tax Category, not at the main category's rate.
Set the tax of one product
Edit the product
Open the product from the Catalogue menu.
Choose its tax category
In Tax category, below Category, pick one of:
| Choice | Result |
|---|
| Category Tax | The product follows its product category |
| A named tax category | The product uses that rate, whatever its category says |
The Tax category field is shown only while tax and tax categories are both on. It is required on the form, and it is not shown on an individual variant.
Variants do not take their parent product's tax category. Each variant follows the product category. For a product with variants, set the rate on its category.
Check your work
Open Shop › Tax Categories. Each row counts the product categories and products that name it directly, or shows Not assigned yet. A product set to Category Tax is not counted as a product; its category is counted.
What customers see
A rate set to Don't include it is added at checkout. A rate set to Already include this tax leaves the price as it is and shows the tax inside it on the invoice. Orders already placed do not change.