PHP convert and format bytes function

convert_bytes.php

<?php
function convertBytes(int $bytes, string $convert_to = 'KB', bool $format = true, int $decimals = 2): float
{
    if ($convert_to == 'KB') {
        $value = ($bytes / 1024);
    } elseif ($convert_to == 'MB') {
        $value = ($bytes / 1048576);
    } elseif ($convert_to == 'GB') {
        $value = ($bytes / 1073741824);
    } elseif ($convert_to == 'TB') {
        $value = ($bytes / 1099511627776);
    } else {
        $value = $bytes;
    }
    if ($format) $value = number_format($value, $decimals);
    return $value;
}