- Connect to the Gmail admin account via https://www.google.com/gmail/ or https://admin.google.com/
- Click on your picture at the top right corner and click on ‘Manage your Google account.’
3. Look for ‘Account Storage’ tile and click on ‘Manage Storage’.
4. In the Drive Storage window, you will be able to see how much is the size of Google Drive and how big is the mailbox under the ‘Gmail’ section.