Microsoft Exchange Online Limits
This article offers guidance on information regarding Microsoft Exchange Online limits.
The limits in Microsoft Exchange Online fall into one of the following categories:
- Address book limits
- Mailbox storage limits
- Capacity alerts
- Mailbox folder limits
- Message limits
- Receiving and sending limits
- Reporting and message trace limits
- Retention limits
- Distribution group limits
- Journal, Transport, and Inbox rule limits
- Moderation limits
- Exchange ActiveSync limits
- The limits applied to a Microsoft Office 365 organization may differ depending on how long the University of Chicago has been enrolled in the service.
- When a limit is changed in the Microsoft data centers, it can take some time to apply the change to all existing customers.
- You can't modify most of these limits, but you should be aware of them.
- These limits apply to both internal and external recipients.
- By default, Exchange Online Protection (EOP) protects Exchange Online mailboxes.
- For limits that apply to EOP features in Exchange Online, see Exchange Online Protection Limits.