Add a minimum WooCommerce order amount

A client had Carding attacks on his WooCommerce store. The result was very small orders that all end up failed. To stop this carding attack I added a minimum order. This effectively stopped Carding attacks and it also a good way to add a minimum order to a store.

Inspired by Business Bloomer – WooCommerce define a minimum order amount.
I then worked with ChatGPT on a new code.

• Set a $30 minimum order amount.
• If below minimum order amount disable checkout button.
• If someone enters the checkout page without having a minimum order in place they will be redirected to the cart page.

The final result of the minimum order subtotal amount code.

Added to a Code snippet plugin.

// Set the minimum order amount (based on subtotal)
function custom_wc_minimum_order_amount() {
    return 30;
}

// Show error notice if subtotal is below minimum
function custom_wc_minimum_order_notice() {
    if ( is_admin() || ! is_cart() || defined( 'DOING_AJAX' ) ) return;

    $minimum = custom_wc_minimum_order_amount();
    $total = WC()->cart->get_subtotal();

    if ( $total > 0 && $total < $minimum ) {
        // Avoid duplicate notices
        $notices = wc_get_notices( 'error' );
        foreach ( $notices as $notice ) {
            if ( isset( $notice['notice'] ) && strpos( $notice['notice'], 'minimum order amount' ) !== false ) {
                return;
            }
        }

        wc_add_notice(
            sprintf(
                'Your current order total is %s — the minimum order amount is %s.',
                wc_price( $total ),
                wc_price( $minimum )
            ),
            'error'
        );
    }
}
add_action( 'woocommerce_cart_loaded_from_session', 'custom_wc_minimum_order_notice' );
add_action( 'woocommerce_before_cart', 'custom_wc_minimum_order_notice', 5 );

// Disable "Proceed to checkout" button if below minimum
function custom_wc_disable_checkout_button_below_minimum() {
    if ( ! is_cart() ) return;

    $minimum = custom_wc_minimum_order_amount();
    $total = WC()->cart->get_subtotal();

    if ( $total > 0 && $total < $minimum ) {
        ?>
        <style>
            .checkout-button {
                pointer-events: none;
                opacity: 0.5;
                cursor: not-allowed !important;
            }
        </style>
        <?php
    }
}
add_action( 'woocommerce_proceed_to_checkout', 'custom_wc_disable_checkout_button_below_minimum', 20 );

// Block checkout access if subtotal is below minimum
function custom_wc_block_checkout_if_below_minimum() {
    if ( is_admin() || ! is_checkout() || defined( 'DOING_AJAX' ) ) return;

    if ( WC()->cart && ! WC()->cart->is_empty() ) {
        $minimum = custom_wc_minimum_order_amount();
        $total = WC()->cart->get_subtotal();

        if ( $total < $minimum ) {
            wc_add_notice(
                sprintf(
                    'Your current order total is %s — the minimum order amount is %s.',
                    wc_price( $total ),
                    wc_price( $minimum )
                ),
                'error'
            );
            wp_safe_redirect( wc_get_cart_url() );
            exit;
        }
    }
}
add_action( 'template_redirect', 'custom_wc_block_checkout_if_below_minimum', 5 ); // Priority 5 = early

CSS code used

.woocommerce-error {
    border: 1px solid #d63638;
    background-color: #fcebea;
    color: #a00e0e;
    border-radius: 4px;
    list-style: none;
}

.woocommerce-error li {
    list-style: none;
	position: relative;
}

.site-main .entry-content ul li, .site-main .entry-content ol li {
    position: relative;
    padding-left: 30px !important;
}