Microsoft Exchange is cracking down on spam with new bulk sending limits

Microsoft Exchange on laptop
(Image credit: monticello /

Microsoft is setting a limit on the amount of bulk emails users can send in a day with Exchange Online.

From January 2025, the email server will allow no more than 2,000 external recipients of bulk emails per day, in order to prevent users from abusing the service, which wasn't even designed for sending emails in bulk.

In a blog post detailing the changes, Microsoft states that there is currently no limit on bulk sending in Exchange Online to external recipients. With the introduction of an External Recipient Rate (ERR), however, there soon will be. 

Switching services

The tech giant also notes that the total Recipient Rate limit will remain at 10,000 per day, adding that, once the ERR limit takes effect, "if you send to less than 2,000 external recipients in a 24 hour period, you will still be able to send to 10,000 total recipients."

There will be two phases to the change: phase 1 will see the ERR limit applied to cloud-hosted mailboxes of all newly created tenants, starting from January 2025. Phase 2 will take place between July and December that same year, where the ERR limit will be applied to existing tenants.

If organizations need to send bulk emails to more than 2,000 recipients, Microsoft recommends that they switch to using Azure Communications Services for Email, which the company says "is designed specifically for high volume email sent to recipients external to your tenant."

The change follows hot on the heels of Google's recent bulk sending changes to Gmail. As the email provider celebrated its 20th birthday, it added new security features, one of which was to set new rules for organizations sending bulk emails, again with the aim of helping to prevent spam, with Yahoo also recently introducing similar measures.


Lewis Maddison
Reviews Writer

Lewis Maddison is a Reviews Writer for TechRadar. He previously worked as a Staff Writer for our business section, TechRadar Pro, where he had experience with productivity-enhancing hardware, ranging from keyboards to standing desks. His area of expertise lies in computer peripherals and audio hardware, having spent over a decade exploring the murky depths of both PC building and music production. He also revels in picking up on the finest details and niggles that ultimately make a big difference to the user experience.