Woocommerce sale-flash.php for percentages

sale-flash.php

<?php
/**
 * Single Product Sale Flash
 *
 * This template can be overridden by copying it to yourtheme/woocommerce/single-product/sale-flash.php.
 *
 * HOWEVER, on occasion WooCommerce will need to update template files and you
 * (the theme developer) will need to copy the new files to your theme to
 * maintain compatibility. We try to do this as little as possible, but it does
 * happen. When this occurs the version of the template file will be bumped and
 * the readme will list any important changes.
 *
 * @see 	    https://docs.woocommerce.com/document/template-structure/
 * @author 		WooThemes
 * @package 	WooCommerce/Templates
 * @version     1.6.4
 */
if ( ! defined( 'ABSPATH' ) ) {
	exit; // Exit if accessed directly 
}
global $post, $product;
?>

<?php if ( $product->is_on_sale() ) : ?>

	<?php
	if ($product->is_type( 'simple' )) {
		$sale_price     =  $product->get_sale_price();
		$regular_price  =  $product->get_regular_price();
	}
	elseif($product->is_type('variable')){
		$sale_price     =  $product->get_variation_sale_price( 'min', true );
		$regular_price  =  $product->get_variation_regular_price( 'max', true );
	}


	$discount = round (($sale_price / $regular_price -1 ) * 100);

	?>

	<?php echo apply_filters( 'woocommerce_sale_flash', '<span class="onsale-icon"> ' . $discount . ' %</span>', $post, $product ); ?>

<?php endif;
/* Omit closing PHP tag at the end of PHP files to avoid "headers already sent" issues. */