Microsoft Expands Mailbox Storage From 50 GB to 100 GB for Users
Brief
Microsoft has started expanding primary mailbox storage for Microsoft 365 Business Basic, Business Standard, and Business Premium users. Eligible users can now receive up to 100 GB of Exchange Online mailbox capacity , doubling the previous 50 GB entitlement.
The change is part of Microsoft’s 2026 packaging updates, which began rolling out in June and are expected to continue through September. Microsoft also issued advance tenant notifications through the Message Center before the service-plan changes became available.
The increased capacity applies only to the primary mailbox. It does not automatically provide archive mailbox features , compliance capabilities, or other benefits of Exchange Online Plan 2.
Microsoft Expands Mailbox Storage
Microsoft delivers the new 100 GB entitlement through two Exchange-related service plans.