Microsoft doubles Exchange Online mailbox storage to 100 GB

Microsoft is doubling the mailbox storage capacity for specific Microsoft 365 Business subscription tiers. Users on Business Basic, Business Standard, and Business Premium plans will see their primary mailbox capacity increase from 50 GB to 100 GB.

The upgrade is being implemented automatically through a combination of service plans. The new total is achieved by pairing the existing 50 GB base plan with an additional 50 GB service package. This rollout began in early summer and is expected to be completed for all eligible accounts by September 2026.

This expansion aims to address the growing demand for digital storage in corporate environments, where email volumes and attachment sizes have increased significantly. The update allows businesses to avoid upgrading to more expensive Enterprise licenses solely to increase storage limits. However, manually configured lower storage limits set by administrators will remain in effect and will not be overwritten by the automatic increase.