Below are some of the limits for Microsoft 365 accounts.
The Microsoft 365 email system was changed to set the maximum message size send/receive limits to 150mb. This change was made to allow easier collaboration within the University of Iowa. Please keep the following in mind:
- Maximum total message send/receive size is 150mb. This includes both the message content and attachments.
- Attaching a large file to an email message requires uploading that file to the email system. This can increase the time required to send the message.
- Email attachments count against overall email storage quota.
- While the UI email systems allow sending and receiving 150mb email messages (including attachments), other external email systems continue to have smaller limits. Some common receiving limits are:
- Gmail – 50mb
- Outlook.com – 50mb
- Yahoo – 25mb
- Peer universities – varies
- Whenever possible, it is advised to use a file collaboration tool for large files. The University of Iowa supports Microsoft OneDrive for Business which allows for file sizes larger than 150mb.
| LIMIT TYPE | Outlook (Windows) |
Microsoft 365.com (Outlook on the web) |
Outlook (Mac) |
Outlook for iOS and Android | Encrypted Messages |
|---|---|---|---|---|---|
| Message send/receive size limit (including attachments) - Keep in mind that someone's mailbox on the Microsoft 365 server will be prohibited from receiving messages if they exceed their maximum quota limit. Note: when you attach a file to a message, the file size of the attachment increases (it can increase as much as 30% in size when it is sent). Microsoft Message Limits | 150 MB | 112 MB | 150 MB | 33 MB | 25 MB |
| Storage - User Mailbox, Shared Mailbox, Resource Mailbox | 100 GB | 100 GB | 100 GB | 100 GB | 100 GB |
NOTE: Microsoft has implemented Receiving and Sending Limits. They have stated that Microsoft 365 is not meant to be a bulk email service. "Exchange Online customers who need to send legitimate bulk commercial email (for example, customer newsletters) should use third-party providers that specialize in these services."
Quota Alerts Across Office 365:
Warning: 99GB
Prohibit Send: 99.5 GB
Prohibit Send/Receive: 100 GB
More detailed information can be found at Exchange Online Limits