Office 365 Message & Recipient Limits

When it comes to sending messages through Microsoft 365, you may have some questions that directly affect your email experience:

  • Are any sending size limits applied to email messages?
  • What recipient limits are applied to email messages?

The limits on messages, mailboxes, recipients, and email clients fall into one of the following categories:

  • Message limits
  • Recipient and sender limits
  • Retention limits
  • Distribution group limits
  • Transport rule limits
  • Moderation limits

Important - Please be aware of the following:

  • The limits applied to your domain may differ depending on how long your domain has been enrolled in the service. When a limit is changed in the Microsoft datacenters, 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.

1.) Message limits

An image of message limits.

  • These limits are applied to every email message.

2.) Recipient and sender limits

An image of recipient and sender limits.

  • These limits are applied to messages, senders, and recipients to combat spam and mass-mailing worms or viruses.
  • Note: For distribution groups stored in the shared address book, the group is counted as one recipient. For distribution groups stored in the Contacts folder of a mailbox, the members of the group are counted individually.

3.) Retention limits

An image of retention limits.

  • These limits control the amount of time that items in specific folders in the Inbox are accessible.

4.) Distribution group limits

An image of distribution group limits.

  • These limits apply to distribution groups.

5.) Transport rule limits

An image of transport rule limits.

  • These limits control organization-wide rules, als known as transport rules.

6.) Moderation limits

An image of moderation limits.

  • These limits control moderation settings used for message approval applied to distribution groups and transport rules.

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Article ID: 79019
Thu 5/23/19 11:55 AM
Wed 5/1/24 4:10 PM
Internal or External