Each Office 365 mailbox has a storage capacity of 25 GB. For many, this is more than enough storage and there will be no need to worry about reaching capacity.
You have two ways to check how much storage you are using.
- In Outlook – right click on the status bar; make sure Quota Information is turned on with a check mark; and your available storage will be displayed in the lower left-hand corner
- From the web at portal.microsoftonline.com, click Options from the portal page or within Outlook
to display your current usage: