Email Limits

Account Limits

  • Mailbox Limit: 50GB
  • Messages Limit: 1 Million messages per mailbox folder

Message Limits*

  • Message Size - Outlook for Windows: 150MB
  • Message Size - Outlook on the Web: 112MB
  • Message Size - Outlook for Mac: 35MB
  • Subject length: 255 characters
  • File attachments : 250 attachments
  • Attachment size limit - Outlook for Windows: 150MB
  • Attachment size limit - Outlook for Mac: 35MB
  • Attachment size limit - Outlook on the Web: 35MB

*These are the sending limitations set in place on W-Exchange. The recipient's email service may enforce different limitations. 

Recipient and sender limits

  • Recipient rate limit: 10,000 recipients per day
  • Recipient limit per message: 500 recipients
  • Message rate limit: 30 messages per minute

For more limits, please see this Microsoft help document.