How to determine the max file upload limit in php

Question

How can the file upload size allowed by php settings be determined withing a php script?

Answer 1

Here's a single function, implementing the original idea from AoEmaster. The function returns integer (amount of bytes).

function _GetMaxAllowedUploadSize(){
    $Sizes = array();
    $Sizes[] = ini_get('upload_max_filesize');
    $Sizes[] = ini_get('post_max_size');
    $Sizes[] = ini_get('memory_limit');
    for($x=0;$x

If you want, you can combine it with the following function that renders the output as a human readable text.

function _Byte2Size($bytes,$RoundLength=1) {
    $kb = 1024;         // Kilobyte
    $mb = 1024 * $kb;   // Megabyte
    $gb = 1024 * $mb;   // Gigabyte
    $tb = 1024 * $gb;   // Terabyte

    if($bytes < $kb) {
        if(!$bytes){
            $bytes = '0';
        }
        return (($bytes + 1)-1).' B';
    } else if($bytes < $mb) {
        return round($bytes/$kb,$RoundLength).' KB';
    } else if($bytes < $gb) {
        return round($bytes/$mb,$RoundLength).' MB';
    } else if($bytes < $tb) {
        return round($bytes/$gb,$RoundLength).' GB';
    } else {
        return round($bytes/$tb,$RoundLength).' TB';
    }
}

Use it this way:

echo 'Max allowed upload size: '._Byte2Size(_GetMaxAllowedUploadSize());

A result could be:

Max allowed upload size: 500 MB