Bulk Email Sending limits

• Bulk email sending limits are applied to the number of recipients you are sending to, rather than the number of emails you are sending.
• Recipient limits are evaluated over a rolling 24-hour period, not a calendar day and do not reset at midnight.
• Recipient rate limits are applied to the user account sending the message, even when sending from a shared mailbox. Messages sent from your own mailbox and from shared mailboxes are combined and evaluated against the relevant limit. 

These limits help prevent misuse, reduce the risk of spam being sent from compromised accounts and improve the likelihood that legitimate messages are delivered successfully to external parties. 

• A single email message can be sent to up to 500 recipients. 
• This includes recipients in the To, Cc, and Bcc fields combined. 
• Address book distribution lists count as one recipient internally, regardless of how many people are included in the list. 

• Staff mailboxes can send to up to 10,000 recipients within any rolling 24-hour period. 
• This total includes both internal and external recipients combined. 
• Because the limit is rolling, it does not reset at midnight. Capacity becomes available again as earlier messages fall outside the 24-hour window. 

• Student mailboxes can send to up to 250 recipients within any rolling 24-hour period. 
• This includes both internal and external recipients combined. 

• Mailboxes are limited to 30 messages per minute. 
• This limit applies regardless of how many recipients are included in each message.