PHP Filesize with label - This custom PHP function reads the file size from a selected file and convert the number of bytes into KB, MB etc. Just define the file name, the file path and the size is returned by the function.

PHP-Filesize-with-label.php

<?php
function file_size($file, $path = "") {
    define("DOCUMENT_ROOT", dirname(__FILE__); // better you define this in the root
    $bytes = array("B", "KB", "MB", "GB", "TB", "PB");
    $file_with_path = DOCUMENT_ROOT."/".$path."/".$file;
    // replace (possible) double slashes with a single one
    $file_with_path = str_replace("//", "/", $file_with_path);
    $size = filesize($file_with_path);
    $i = 0;
    while ($size >= 1024) { //divide the filesize (in bytes) with 1024 to get "bigger" bytes
        $size = $size/1024;
        $i++;
    }
    if ($i > 1) {
        // you can change this number if you like (for more precision)
        return round($size,1)." ".$bytes[$i];
    } else {
        return round($size,0)." ".$bytes[$i];
    }
}
// example 
echo file_size("example.txt", "myFolder");