PHP: File Size Bytes Converter

PHP Bytes to KB, PHP KB to MB, and PHP MB to GB.

<?php
$fileSize = $_FILES['fileName']['size'];

// to KiloBytes
round(($fileSize / 1024), 2);

// to MegaBytes
round(($fileSize / 1048576), 2);

// to GigaBytes
round(($fileSize / 1073741824), 2);