human_readable_bytes_helper.php

if (! function_exists('human_readable_bytes')) {

    /**
     * Convert bytes in a human readable value.
     *
     * According to the specifications, for storage purpose use "metric" system.
     *
     * @see    https://stackoverflow.com/a/38659168
     * @see    https://en.wikipedia.org/wiki/Binary_prefix
     * @param  string  $bytes
     * @param  int     $decimals
     * @param  string  $system
     * @return string
     */
    function human_readable_bytes(string $bytes, int $decimals = 2, string $system = 'metric'): string
    {
        if (! in_array($system, ['binary', 'metric'])) {
            $system = 'metric';
        }

        $mod = ($system === 'binary') ? 1024 : 1000;

        $units = array(
            'binary' => ['B', 'KiB', 'MiB', 'GiB', 'TiB', 'PiB', 'EiB', 'ZiB', 'YiB'],
            'metric' => ['B', 'kB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'],
        );

        $factor = floor((strlen($bytes) - 1) / 3);

        return sprintf("%.{$decimals}f%s", ((float) $bytes / ($mod ** $factor)), $units[$system][$factor]);
    }
}