How to add conditional fees in WooCommerce

Write down exactly when the fee applies, how much it costs, whether it is taxable, and what customers should see at checkout. For example: add a £3 handling fee when the cart subtotal is below £50, but do not add it when a free-shipping coupon is active.

Decide whether the rule uses the subtotal, shipping-inclusive total, product quantity, selected payment method, customer location or shipping method. Ambiguous rules are where duplicate charges and unexpected fees usually start.

For one or two straightforward conditions, custom code is a reasonable option. WooCommerce recalculates cart fees during totals calculation, so the normal approach is to attach a callback to woocommerce_cart_calculate_fees and add the fee with the cart’s fee method. Fees are not persistent cart items and must be added again whenever totals are recalculated.

The drawback is maintenance. You must handle tax status, coupons, logged-in users, checkout refreshes, payment methods and future WooCommerce changes yourself. Do not put the code directly in a parent theme’s functions.php, because a theme update can remove it; use a child theme or a snippets plugin instead.

For a basic fixed fee, add a snippet through your child theme or a code-snippet tool. This example adds a £3 fee when the cart subtotal is below £50:

add_action( 'woocommerce_cart_calculate_fees', function( $cart ) { if ( is_admin() && ! defined( 'DOING_AJAX' ) ) { return; } if ( $cart->get_subtotal() < 50 ) { $cart->add_fee( 'Small order handling', 3, false ); } } );

Change the label, threshold and amount to suit your rule. Add further checks inside the condition when needed, but avoid adding the same fee from more than one callback. WooCommerce’s documented fee API supports fixed and percentage-style calculations, and the fee can be marked taxable when appropriate.

Payment-method fees need the selected gateway from the WooCommerce session, while location rules should read the customer’s billing or shipping address. These values can change during checkout, so the fee must be recalculated after the customer updates the form. WooCommerce specifically documents server-side fee calculation for selected payment methods using the cart fee hook.

Be careful with subscriptions: fees added through the cart calculation hook can apply to recurring carts unless you deliberately restrict them. Also check whether your store uses the Cart and Checkout blocks. Some shortcode hooks do not work in the block experience, and an incompatible extension may require switching back to the classic checkout.

Test the cart, classic checkout and block checkout if your store uses both. Check the fee with the condition met and not met, then test coupons, shipping changes, guest customers, logged-in customers, tax display, refunds and the order confirmation email.

Look for the most common failure: the fee appears twice after an AJAX checkout refresh. That normally means the callback is registered twice or another plugin is adding the same fee. Also confirm that a percentage fee is calculated from the intended base and that subscription fees are not being charged again by mistake.

If you need several conditions, the faster route is a rule-based fee plugin rather than maintaining custom PHP. WPC Smart Fees for WooCommerce is a suitable option when you need fixed or percentage fees based on cart values, products, customers, locations, coupons, shipping methods or time windows. It also provides taxable-fee settings, notices, fee-stacking controls and rule import/export.

Create a rule, choose whether the amount is fixed or percentage-based, set the conditions, enter the customer-facing label, choose the tax treatment, then save. Recreate the examples from your manual plan and test each rule independently before enabling several rules together. Check the plugin’s current Cart and Checkout block compatibility before using it on a block-based checkout, because WooCommerce advises checking extension compatibility for the block experience.