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.](https://elon.teamdynamix.com/TDPortal/Images/Viewer?fileName=bce029e6-fcef-4b80-bb19-f64b7dee72a5.png)
- These limits are applied to every email message.
2.) Recipient and sender limits
![An image of recipient and sender limits.](https://elon.teamdynamix.com/TDPortal/Images/Viewer?fileName=230d6891-0cb6-4499-90ed-865f8989ec07.png)
- 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.](https://elon.teamdynamix.com/TDPortal/Images/Viewer?fileName=648dd18e-f75d-4ca7-af7c-e4e0f4600944.png)
- 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.](https://elon.teamdynamix.com/TDPortal/Images/Viewer?fileName=2f20942c-2a3d-47fc-9dbb-d96839523d03.png)
- These limits apply to distribution groups.
5.) Transport rule limits
![An image of transport rule limits.](https://elon.teamdynamix.com/TDPortal/Images/Viewer?fileName=40b04c1a-d61a-41af-b3bb-6f54fa5471d8.png)
- These limits control organization-wide rules, als known as transport rules.
6.) Moderation limits
![An image of moderation limits.](https://elon.teamdynamix.com/TDPortal/Images/Viewer?fileName=5802fdd0-f44c-4b99-aa00-cfca70893014.png)
- These limits control moderation settings used for message approval applied to distribution groups and transport rules.