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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
- These limits are applied to every email message.
2.) Recipient and sender limits
| Limit |
Students |
Faculty and staff |
-
Maximum recipients per message
(Combined total of To:, Cc:, and Bcc: fields)
|
500
|
500
|
-
Allowed external recipients per hour
|
500
|
500
|
-
Allowed internal recipients per hour
|
500
|
1,000
|
-
Total recipients (internal and external) per day
|
500
|
5,000
|
|
|
30
|
30
|
-
Automatic forwarding to external addresses
|
Not allowed
|
Not allowed
|
-
What happens when the sending limit is reached
|
The account is blocked from sending email
|
The account is blocked from sending email
|
These limits help prevent spam and mass-mailing viruses by controlling messages, senders, and recipients.
Note: Distribution groups in the shared Global Address Book count as one recipient.
Personal Contact groups in a mailbox’s Contacts folder count each member separately.
3.) Retention limits
- These limits control the amount of time that items in specific folders in the Inbox are accessible.
4.) Distribution group limits
- These limits apply to distribution groups.
5.) Transport rule limits
- These limits control organization-wide rules, als known as transport rules.
6.) Moderation limits
- These limits control moderation settings used for message approval applied to distribution groups and transport rules.