formatting into Kilobytes, Megabytes...//echo formatBytes(24962496);// 23.81M//echo formatBytes(24962496, 0);// 24M//echo formatBytes(24962496, 4);// 23.8061M

format_bytes.php

function formatBytes($size, $precision = 2)
{
    $base = log($size) / log(1024);
    $suffixes = array('', 'k', 'M', 'G', 'T');   

    return round(pow(1024, $base - floor($base)), $precision) . $suffixes[floor($base)];
}