Check used memory for PHP script running

<?php
    function bytesConvert($bytes) {
        $ext = array('B', 'kB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB');
        $unitCount = 0;
        for(; $bytes > 1024; $unitCount++) $bytes /= 1024;
        return round($bytes, 2) ." ". $ext[$unitCount];
    }
echo "Memory used: ". bytesConvert(memory_get_usage());

// do yourFunction here

echo "\n";
echo "Memory used: ". bytesConvert(memory_get_usage());
?>