PHP: Output a number of bytes in human readable form


Would you be able to say how much 167892598784 bytes are without spending quite some time thinking about it first? Large amounts of bytes are rarely very readable to people. Not for me anyways.

Just stumbled over a handy function to make that number of bytes a bit more readable for us humans. I found it in a comment in the PHP manual and figured I could note it down here so I don't lose it and in case someone else could need it. Functions like these are just bound to come in handy some day...

Let me know if you have a better name for it, but here it is 🙂

Update 2013-04-11: Added zero check (prevents crash if $bytes is zero) and abs call (prevents crash when $bytes is negative)

function make_pretty($bytes)
    $symbols = array('B', 'KiB', 'MiB', 'GiB', 'TiB', 'PiB', 'EiB', 'ZiB', 'YiB');

    if($bytes == 0)
        return sprintf('%.2f '.$symbols[0], 0);

    $exp = floor(log(abs($bytes)) / log(1024));

    return sprintf('%.2f '.$symbols[$exp], $bytes/pow(1024, floor($exp)));

Usage example

echo make_pretty(167892598784); //  156.36 GiB
echo make_pretty(719267016);    //  685.95 MiB
echo make_pretty(114893);       //  112.20 KiB
echo make_pretty(6218);         //  6.07 KiB
echo make_pretty(42);           //  42.00 B
echo make_pretty(0);            //  0.00 B
echo make_pretty(-50);          // -50.00 B

That was it for now 🙂