How to check my M365 mailbox usage?

You can check your M365 mailbox quota and usage in the "Options" of Microsoft 365 Outlook Web App (OWA):

  1. Login your M365 account at CityU Staff Sign in to Microsoft 365 web page.
  2. Click gear icon at the top-right corner of OWA window.
  3. Select Mail under Your app settings.

  4. Select My account under General. The Mailbox usage of your mailbox will be shown.

    Mailbox Usage


Return to FAQs on CityU Microsoft 365