What are the limits for Office 365 email?


A @purdue.edu email account is provided to all individuals who maintain an affiliation with Purdue University. Your address will remain the same, regardless of your employing department or student major information changes.

All email sent to @purdue.edu email addresses is scanned for viruses and is spam scanned.


The following are the current limits for Exchange Online (Office 365).   These limits are not negotiable and CANNOT be increased.   

For instructions on how to check your current mailbox size, how to clean up your mailbox, and how to permanently delete email, see Microsoft’s knowledge base article: “Mailbox storage limits in Outlook” 

Note: Phishing emails often attempt to create panic in users by claiming “email quota exceeded” or other similar messages. If such a message has been received, you can verify its authenticity by sending it to abuse@purdue.edu.  

Mailbox quota limits   

  • Default mailbox:  100 GB 

  • Archive mailbox:  100 GB-Separate from your default mailbox, must be requested through Purdue IT Messaging, and can only be viewed/accessed through Outlook or OWA 

Sending limits   

  • Recipients per day: 10,000-Each address on the To, Cc, or Bcc field is considered a recipient 

  • Recipients per message: 500-Sending a message to a list counts as a single recipient, even if the list contains thousands of members 

  • Messages per minute: 30 

Receiving limits 

  • Messages per hour: 3600-After one hour, the limit will refresh and the mailbox will once again be able to receive messages 

Message Size limits  

Please keep in mind this is ONLY for Office 365 messages and doesn't mean that other mail providers (Mailman, Hotmail, Gmail) will allow these sizes.   

  • Message size in Outlook (Windows or Mac): 150 MB-This is the overall message, including any attachments. 

  • Message size in OWA:  112 MB 

  • Subject length: 255 characters   

Attachment limits 

  • Attachments per email: 250-Even if the total size of all the file attachments doesn't violate the message size limit, there is still a limit on how many attachments are allowed in the message. 

  • Attachment size in Outlook (Windows or Mac):  150 MB 

  • Attachment size in OWA:  35 MB 

  • Embedded message depth:  30-The maximum number of forwarded email messages that are allowed in an email message. 


Still need help?  Click the 'Purdue IT Request' button to start a ticket.

Purdue IT Request


Article ID: 576
Mon 1/29/24 4:20 PM
Mon 1/29/24 4:21 PM

Related Services / Offerings (2)

Email and calendaring are essential day-to-day tools for everyone. Using them effectively is key.
Email & Calendaring Request