How to Add a Custom Fee in WooCommerce (Code)

Add a custom fee in WooCommerce with the woocommerce_cart_calculate_fees hook and $cart->add_fee( $name, $amount, $taxable, $tax_class ). The fee shows as its own line in the cart and checkout totals and applies to the whole cart, not a single product. Use code for a fixed or percentage fee, guard it so it does not run in the admin, and keep the fee name unique so it is not added twice. For conditional, no-code fees, the Extra Fees plugin handles it from the admin.

A custom fee is any charge you add on top of product price and shipping: a handling fee, a rush charge, a payment surcharge, a gift-wrap fee, or an eco fee. WooCommerce shows it as a separate line in the cart and checkout totals.

This guide takes the code-first route, because that gives you precise control over a single fee in functions.php. If you would rather set conditional fees by city, user role, payment method, or cart total without writing code, our companion guide on how to add extra fees in WooCommerce covers the no-code path, and we link the plugin near the end here too.

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What is a custom fee in WooCommerce

A custom fee is a cart-level surcharge, not a change to any product’s price. WooCommerce calculates it during cart totals and lists it under the subtotal and shipping. Because it sits at the cart level, one fee covers the whole order rather than attaching to a specific item.

Common examples:

• Handling or packaging fees on every order.
• Rush or express processing charges.
• Payment surcharges, such as a fee for Cash on Delivery.
• Eco or recycling fees required in some regions.

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Add a custom fee with code

All custom fees run through one hook. You attach a function to woocommerce_cart_calculate_fees, receive the cart object, and call add_fee() on it. The snippets below go in your child theme’s functions.php or a code snippets plugin.

The add_fee() method and its parameters

The method signature is $cart->add_fee( $name, $amount, $taxable, $tax_class ). Here is what each parameter does:

Parameter	Type	What it does
$name	string	The label shown in cart and checkout totals. Must be unique.
$amount	float	The fee value. Use positive amounts only.
$taxable	bool	Whether tax applies to the fee. Defaults to false.
$tax_class	string	The tax class to use when taxable. Blank means the standard class.

1. Add a simple fixed fee

This adds a flat handling fee to every cart.

add_action( ‘woocommerce_cart_calculate_fees’, ‘ds_add_custom_fee’ );

function ds_add_custom_fee( $cart ) {

    if ( is_admin() && ! defined( ‘DOING_AJAX’ ) ) {

        return;

    }

    $cart->add_fee( ‘Handling fee’, 5, false, ” );

}

2. Add a percentage-based fee

WooCommerce has no built-in percentage option, so you calculate the amount from the cart subtotal yourself. This adds a 3 percent service fee.

add_action( ‘woocommerce_cart_calculate_fees’, ‘ds_add_percentage_fee’ );

function ds_add_percentage_fee( $cart ) {

    if ( is_admin() && ! defined( ‘DOING_AJAX’ ) ) {

        return;

    }

    $percentage = 0.03; // 3 percent

    $fee = ( $cart->get_cart_contents_total() + $cart->get_shipping_total() ) * $percentage;

    $cart->add_fee( ‘Service fee (3%)’, $fee, true, ” );

}

3. Add a conditional fee

You can add a fee only when a condition is met. This adds a small-order fee when the cart total is under 50.

add_action( ‘woocommerce_cart_calculate_fees’, ‘ds_add_small_order_fee’ );

function ds_add_small_order_fee( $cart ) {

    if ( is_admin() && ! defined( ‘DOING_AJAX’ ) ) {

        return;

    }

    if ( $cart->get_cart_contents_total() < 50 ) {

        $cart->add_fee( ‘Small order fee’, 4, false, ” );

    }

}

The same pattern works for other conditions: read the cart, the customer, or the chosen method, and only call add_fee()when your rule matches. For a fee tied to the payment method, see how to add a fee to a payment method.

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Important gotchas before you ship this

A few things trip people up with custom fees. Check these before you go live:

• Guard against the admin. The is_admin() check at the top of each snippet stops the fee from firing in wp-admin while still allowing it during AJAX cart updates.
• The callback runs on every recalculation. It fires on cart load, every AJAX update, and each checkout refresh. Keep it idempotent and never add the same fee twice in one pass.
• Fee names must be unique. Two fees with the same name conflict, so give each one a distinct label.
• Fees are cart-level, not per-product. A custom fee applies to the whole order. To charge by item or quantity, calculate the amount from the cart contents, as in the quantity-based fee approach.
• Payment-method fees need a refresh. A fee that depends on the selected gateway needs JavaScript to trigger update_checkout so totals recalculate when the customer switches methods.
• Avoid negative amounts. WooCommerce does not properly support negative fees as discounts, and a known quirk applies tax to a negative fee even when you set it as non-taxable. Use a coupon for discounts instead.

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No-code alternative: the Extra Fees plugin

Code is the right tool for one or two fixed rules you are comfortable maintaining. Once the conditions multiply, hand-coded fees get hard to manage and easy to break.

The Extra Fees Plugin for WooCommerce does the same job from the admin, with no code to maintain. You build fee rules based on the city, country, user role, payment method, cart total, quantity, or shipping method, set fixed or percentage amounts, and stack multiple rules in the order you want. It is the better route when fees vary by condition or you would rather not touch functions.php. For the full no-code walkthrough and conditional use cases, see the guide to adding extra fees in WooCommerce and how to set conditional fees at checkout.

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Best practices

Keep these in mind so your custom fee behaves at checkout:

• Always include the admin guard so the fee does not fire in the dashboard.
• Use unique, customer-friendly fee labels, since buyers see them in the totals.
• Decide tax treatment deliberately by setting the $taxable parameter, and confirm it on a test order.
• Test a full checkout, including an AJAX cart update, to confirm the fee shows once and recalculates correctly.
• Move to the plugin once you need conditional rules across many products, roles, or payment methods.

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Conclusion

Adding a custom fee in WooCommerce comes down to one hook and one method: attach a function to woocommerce_cart_calculate_fees and call add_fee() with a name, an amount, and your tax choice. Guard it against the admin, keep names unique, and compute percentages from the subtotal. That covers fixed, percentage, and simple conditional fees in a few lines. 

When the rules grow conditional or you would rather skip the code, the Extra Fees Plugin for WooCommerce sets the same fees from the admin without maintaining a snippet.

Frequently asked questions