Tax-Proof Coupons for WooCommerce

A fixed-amount gross gift certificate remains a fixed-amount gross gift certificate

By default, WooCommerce calculates fixed-cart coupons as a net discount before tax. If the entered amount is intended to be a visible gross value, its actual effect may therefore vary depending on the tax rate or tax jurisdiction.

What the Plugin Changes

In the Coupon Editor, the Fixed-Cart Coupons plugin adds the option Apply coupon after tax. When enabled, the plugin distributes the gross amount among the product lines eligible for a discount and calculates the net discount required by WooCommerce for each portion using the applicable tax rate.

• The displayed voucher value remains constant within the currency rounding tolerance.
• Mixed tax rates are applied on a per-item basis for each product line eligible for a discount.
• The discount is limited to the eligible gross merchandise value; shipping, fees, and excluded products do not increase this limit.
• Gross, net, and tax amounts are stored in the "Coupon" field of the order.

Compatibility and Limitations

The plugin includes its own compatibility paths for Checkout Block, HPOS, WPML/WooCommerce Multilingual, and Germanized Pro/StoreaBill. However, its actual functionality depends on the versions and store configuration and should be tested with realistic sample orders before deployment in a production environment.

It does not select tax rates, change product prices, or replace any tax or billing engine, and it does not provide tax or legal advice. Percentage and fixed-amount product coupons retain WooCommerce's default behavior.