Access ‘Files’ from the main menu.
On this page you’ll see how much storage you’ve used – a combination of all files uploaded, minus any that have been deleted. This also shows how much storage you have left to use on your account.
When a file is deleted, it will reduce the amount of storage used on your account.
It’s also important to note that file storage is allocated per account rather than per user. So your storage will be shared between all the users on your account.