PHP: Get Upload Filesize

functions.php

<?php 
// Return allowed upload filesize in MB.
function get_upload_max_filesize(){
        $upload_max_filesize = (int)(ini_get('upload_max_filesize'));
        $post_max_size = (int)(ini_get('post_max_size'));
        $memory_limit = (int)(ini_get('memory_limit'));
        $allowed_size = min($upload_max_filesize, $post_max_size, $memory_limit);    
 
        return $allowed_size;
    }