I'd like to apply a discount on an order item from the admin panel by using the meta field on the product. There is the option to modify the input price on the right, but you can't do it with a percentage. So my idea is to apply a discount function if exists a meta field. This is my function, but it is not working: function discount_meta($item_id, $item, $order_id){ // Get Order $order = !empty($order) ? $order : wc_get_order($order_id); if (!$order || !is_a($order, '\WC_Order')) { return; } // Go through Order items foreach ($order->get_items() as $item_id => $item) { //Get product Id of the item $product_id = (!empty($item['variation_id']) ? $item['variation_id'] : $item['product_id']); //Get price of the item $price = ($product = wc_get_product($product_id)) ? $product->get_price() : 0; //Update Line Subtotal if exist discount meta if (wc_get_order_item_meta($item_id, 'discount', true)) { $discount = wc_get_order_item_meta($item_id, 'discount', true); $discountval = $price * $discount / 100; $saleprice = $price - $discountval; wc_update_order_item_meta($item_id, '_line_total', $saleprice); } } } add_action('woocommerce_order_before_calculate_totals', 'discount_meta', 10, 3); On the admin panel I'd like to do this: