Mostly we require to calculate for uploaded directory size because we can see how much we size allocate in uploaded directory. If you have limited server then you always need to check how much size of data in my folder.
You can also get size of directory that way you can also display on your admin panel. Laravel provide File facade. File facade through we can get folder size in kb or mb or gb etc.
In bellow example i have images directory in public folder. so we can get size for images folder like this way :
$file_size = 0;
foreach( File::allFiles(public_path('images')) as $file)
$file_size += $file->getSize();
$file_size = number_format($file_size / 1048576,2);