How to get directory size in PHP

function GetDirectorySize($path){
    $bytestotal = 0;
    $path = realpath($path);
    if($path!==false && $path!='' && file_exists($path)){
        foreach(new RecursiveIteratorIterator(new RecursiveDirectoryIterator($path, FilesystemIterator::SKIP_DOTS)) as $object){
            $bytestotal += $object->getSize();
        }
    }
    return $bytestotal;
}

The same idea as Janith Chinthana suggested. With a few fixes:

• Converts $path to realpath
• Performs iteration only if path is valid and folder exists
• Skips . and .. files
• Optimized for performance

The following are other solutions offered elsewhere:

If on a Windows Host:

<?
    $f = 'f:/www/docs';
    $obj = new COM ( 'scripting.filesystemobject' );
    if ( is_object ( $obj ) )
    {
        $ref = $obj->getfolder ( $f );
        echo 'Directory: ' . $f . ' => Size: ' . $ref->size;
        $obj = null;
    }
    else
    {
        echo 'can not create object';
    }
?>

Else, if on a Linux Host:

<?
    $f = './path/directory';
    $io = popen ( '/usr/bin/du -sk ' . $f, 'r' );
    $size = fgets ( $io, 4096);
    $size = substr ( $size, 0, strpos ( $size, "\t" ) );
    pclose ( $io );
    echo 'Directory: ' . $f . ' => Size: ' . $size;
?>