Environment::getPostMaxSize() 

\nn\t3::Environment()->getPostMaxSize(); 

Return maximum upload size for files from the frontend. This specification is the value that was defined in php.ini and, if necessary was overwritten via the .htaccess.

\nn\t3::Environment()->getPostMaxSize(); // e.g. '1048576' for 1MB

| @return integer

public function getPostMaxSize() {
	$postMaxSize = ini_get('post_max_size');
	return \nn\t3::Convert($postMaxSize)->toBytes();
}