Insert a custom total row on cart and checkout totals in Woocommerce

Question

In woocommerce, I have successfully managed to add a custom field to a Woocommerce simple product and display that value on the additional info tab on a product page.

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Answer 1

The following will display the total cart volume in cart and checkout page:

add_action( 'woocommerce_cart_totals_before_shipping', 'display_cart_volume_total', 20 );
add_action( 'woocommerce_review_order_before_shipping', 'display_cart_volume_total', 20 );
function display_cart_volume_total() {
    $total_volume = 0;

    // Loop through cart items and calculate total volume
    foreach( WC()->cart->get_cart() as $cart_item ){
        $product_volume = (float) get_post_meta( $cart_item['product_id'], '_item_volume', true );
        $total_volume  += $product_volume * $cart_item['quantity'];
    }

    if( $total_volume > 0 ){

        // The Output
        echo ' 
            ' . __( "Total Shipping Volume", "woocommerce" ) . '
            ' . number_format($total_volume, 2) . ' m3
        ';
    }
}

Code goes in function.php file of your active child theme (or active theme). Tested and works.