what is the email limit on bulk emails in outlook desktop app

Hi @Mandie Finkelstein, 

Thank you for posting your question in the Microsoft Q&A forum. Based on official Microsoft documentation, here are the definitive daily email sending limits: 

• Daily Recipients (per 24-hour rolling window): 10,000 recipients per user 
• Messages per Minute: 30 messages per minute per mailbox 
• Recipients per Single Message: 1,000 recipients 

In practical terms, this means that when you send emails to individual recipients, you can send up to 10,000 emails within a 24‑hour period. When you send an email to multiple recipients at once using CC or BCC, each message can include up to 1,000 recipients, and those messages are still subject to the overall sending rate limit of 30 messages per minute. 

For reference, you can review the full documentation here:  Exchange Online limits - Service Descriptions | Microsoft Learn 

It’s also important to note that the 10,000‑recipient limit is calculated using a rolling 24‑hour window, not a calendar‑day reset. This means the limit gradually becomes available again as time passes, rather than resetting at midnight. For example, a user sends an email message to 5000 recipients at 09:00 AM, then sends another message to 2500 recipients at 10:00 AM, and then sends another message to 2500 recipients at 11:00 AM, hitting the limit of 10,000 messages. The user won't be able to send messages again until 09:00 AM the next day. 

These limits apply consistently across Outlook desktop app, Outlook web (OWA), and Microsoft 365/Outlook 365 since they all use the same Exchange Online backend infrastructure.  

I hope this information is helpful for your reference. If you have any further questions or need additional clarification, please feel free to reply under this post. 

Thank you for your question. 

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