A simple script that formats the number ob bytes of a file to kb, mb, gb or tb.

function mksize($bytes)
{
	if ($bytes < 1000 * 1024)
		return number_format($bytes / 1024, 2) . " KB";
	elseif ($bytes < 1000 * 1048576)
		return number_format($bytes / 1048576, 2) . " MB";
	elseif ($bytes < 1000 * 1073741824)
		return number_format($bytes / 1073741824, 2) . " GB";
	else
		return number_format($bytes / 1099511627776, 2) . " TB";
}