Guides · Sending limits
How many emails can you send from Outlook and Microsoft 365 a day?
A Microsoft 365 work or school mailbox can send to 10,000 recipients a day and 30 messages a minute. An Outlook.com account with a Microsoft 365 subscription can send to 5,000 recipients a day, and free Outlook.com accounts get less.
Microsoft's limits at a glance
Checked 26 October 2026 against Microsoft's own pages:
| Limit | Figure |
|---|---|
| Recipients a day, per Microsoft 365 mailbox | 10,000, counted over a rolling 24 hours |
| Messages a minute | 30; any extra are delayed, not bounced |
| Recipients in one email | Set by your admin, up to 1,000 |
| Your organisation's outside recipients a day | Depends on how many licences it has; trial organisations get 5,000 |
| Sending from an onmicrosoft.com address | 100 outside recipients a day, for the whole organisation |
| Email size | 35 MB by default; your admin can change it |
| Outlook.com with a Microsoft 365 subscription | 5,000 recipients a day, 500 per email |
| Free Outlook.com and Hotmail | Lower; Microsoft doesn't publish a figure, and new accounts start low |
The extra limit of 2,000 outside recipients a day per mailbox, which Microsoft announced in 2025, was cancelled in January 2026. Some older articles and AI answers still quote it.
Recipients, not emails
Microsoft counts recipients, not emails. An email to 10 people counts as 10. A contact group or distribution list you've made yourself counts every member, so sending to a list of 200 uses 200 of your 10,000.
What happens when you go over
If you go over the daily recipient limit, Microsoft stops your mailbox sending until older emails fall out of the 24-hour window. People you email in the meantime get nothing, and you get non-delivery reports. Microsoft doesn't raise these limits on request.
How long a list takes to send
At Microsoft's 30 messages a minute, with one email per person:
| List size | Time |
|---|---|
| 500 | about 17 minutes |
| 1,000 | about 34 minutes |
| 5,000 | about 2 hours 47 minutes |
| 12,000 | 10,000 on the first day; the rest once the first emails are 24 hours old |
When your mailbox is the wrong tool
Staying under the limit doesn't make bulk marketing acceptable. Microsoft says newsletters and other bulk commercial email should go through a specialist sending service, not Exchange Online. Gmail expects a one-click unsubscribe on marketing email to Gmail users, which Groupmail can't add when it sends through Gmail or Microsoft sign-in.
So use your own address for emails to your own customers, such as quotes, renewals and event invitations. For newsletters and large marketing sends, use a sending service such as SMTP2GO.
How Groupmail 7 paces your sends
These are Groupmail's own built-in limits, not Microsoft's:
- Microsoft 365 account: up to 10,000 emails a day and 1,800 an hour, which matches Microsoft's 30 a minute.
- Outlook.com account: up to 300 a day and 40 an hour. Microsoft publishes no figure for free accounts, so Groupmail uses a cautious limit.
Groupmail counts over a rolling 24 hours. When a send reaches the daily limit, it pauses that account and carries on by itself as the oldest emails pass 24 hours, while Groupmail is open. If Microsoft says you're sending too fast, Groupmail waits and tries again. These built-in limits can't be raised, but you can slow an account down in Settings → Throttle.
Groupmail sends a separate email to each person, so the limit on recipients per email never applies. SMTP2GO and your own mail server have no Groupmail limit; their own plans apply.
Questions people ask
How many emails can I send in a day in Office 365?
10,000 recipients a day from one Microsoft 365 mailbox, counted over a rolling 24 hours, at up to 30 messages a minute.
Can I send 1,000 emails from Outlook?
Yes, from a Microsoft 365 mailbox: 1,000 emails take about 34 minutes at 30 a minute. A free Outlook.com account may not allow it, especially a new one.
Can Outlook send to more than 500 recipients at once?
Your admin sets the limit on recipients per email, up to 1,000. Sending each person their own email avoids that limit entirely.
How do I increase my sending limit in Outlook?
You can't. Microsoft doesn't raise the daily or per-minute limits on request. For bigger sends, use a sending service such as SMTP2GO.
How do I send more than 25 MB in Outlook?
Microsoft 365 allows 35 MB per email by default, and your admin can change it. Through Groupmail's Microsoft sign-in the whole email can be about 3 MB, so for bigger files Groupmail sends through SMTP2GO or your own mail server, or you can share a link instead.
Is there a limit on Outlook mail merge?
Yes, the same limits. Each merged email counts as one recipient against your 10,000 a day.
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