Below are the Hard Sending Limits for Office 365:

Sending Limits	PreAU	Students	Employees	Retirees	Alumni
External Recipients (per hour)	100	1000	1000	1000	100
Internal Recipients (per hour)	100	1000	1000	1000	100
Maximum Recipient (per 24-hour period)	100	1000	1000	1000	100
Maximum Recipient (per email)	100	500	500	500	100

 

The limits listed above are total amounts for a 24-hour period. 

Example: If you are an employee and were to send 800 emails at 8 pm tonight and 200 more at noon tomorrow, you would meet the limit shown above.  These numbers would reset at 8 pm.  If you go over the limit of 1,000 emails in the time period, your email account would be locked for exceeding the email limits.

To have your email account unlocked, please contact the IT Service Desk at (334) 844-4944. 

A potential workaround to the 500-recipient limit per message is to do a mail merge.  In a mail merge Office 365 sends each recipient a separate message, however, the 1,000 limit per day still applies. 

Q: I've exceeded the email limits, and I have contacted the IT Service Desk to have my account unlocked. How do I know which emails were actually delivered before it was locked?

A: When a user exceeds the daily sending limit, emails are usually delivered up to the daily limit. For example, if an employee sends 1,500 emails, Microsoft will stop delivering at 1,000.

However, if a user stuffs any recipient field with more than 500 recipients, Microsoft locks the account from sending, and none of the emails were delivered. After your account is unlocked and you attempt to resend any emails, make sure you are not adding more than 500 recipients per email. Split emails up into smaller recipient totals, also keeping in mind the 1,000 recipient/hour limit for employees.