How to Check how much GB is on the server?

A few months back I found the setting, it would basically go through all the folders and directories adding up the total amount of data on the server. However, recently for the life of me I can't seem to find it. Can anyone tell me where to find it? Thanks.

Shameless Bump... Anyone know?

Right-click a folder and press the "Calculate" button.

Right click folder > Properties > then press calculate button