Tokoo - Sale Percentage

Function.php

add_filter( 'woocommerce_after_shop_loop_item_title', 'bbloomer_show_sale_percentage_loop', 30 );

function bbloomer_show_sale_percentage_loop() {

    global $product;

    if ( $product->is_on_sale() ) {

        if ( ! $product->is_type( 'variable' ) ) {

            $max_percentage = ( ( $product->get_regular_price() - $product->get_sale_price() ) / $product->get_regular_price() ) * 100;

        } else {

            $max_percentage = 0;

            foreach ( $product->get_children() as $child_id ) {
                $variation = wc_get_product( $child_id );
                $price = $variation->get_regular_price();
                $sale = $variation->get_sale_price();
                if ( $price != 0 && ! empty( $sale ) ) {
                    $percentage = ( $price - $sale ) / $price * 100;
                }
                if ( $percentage > $max_percentage ) {
                    $max_percentage = $percentage;
                }
            }

        }

        echo "<div class='sale-perc'>(" . round($max_percentage) . "% OFF)</div>";

    }

}

style.css

.sale-perc {
  color: red !important;
  display: inline;
  padding: .2em .6em .3em;
  font-size: 75%;
  font-weight: normal !important;
  border-radius: .25em;
  background: transparent !important;
}