How many cold emails per mailbox per day?
Short answer
Far fewer than the provider allows. Google Workspace caps a user at 2,000 messages a day and Microsoft 365 at 10,000 recipients a day, but those are anti-abuse ceilings, not targets for cold email. Keep each mailbox at a modest daily volume that its warm-up supports, and add mailboxes on separate domains to grow, rather than pushing one mailbox harder.
In short
- Google Workspace: 2,000 messages per user per day (500 on trial accounts), 3,000 external recipients per day.
- Microsoft 365 (Exchange Online): 10,000 recipients per day and 30 messages per minute per mailbox.
- Gmail and Yahoo require a spam complaint rate below 0.3%; Gmail recommends below 0.1%.
- Volume per mailbox should rise only as the mailbox's warm-up and bounce rate allow.
Last checked:
Provider ceilings, not targets
| Provider | Published limit | Source |
|---|---|---|
| Google Workspace | 2,000 messages per user per day; 500 for trial accounts; 3,000 external recipients per day | Google Workspace |
| Microsoft 365 | 10,000 recipients per day; 30 messages per minute | Microsoft Learn |
Hitting these limits gets a mailbox blocked from sending for up to a day. Long before that, cold email to people who did not ask for it produces complaints and bounces, and those are what mailbox providers judge you on.
What decides the right number
- Mailbox age and warm-up: a new mailbox starts low and rises gradually. See How to warm up a new domain.
- Bounce rate: verify every address first. TechSales marks a mailbox watch at 2% bounces and at risk at 3%.
- Complaint rate: Gmail and Yahoo require under 0.3%. Relevance of the list matters more than volume.
- Domains: spread volume over several mailboxes on secondary domains so one problem does not stop everything.
How TechSales uses mailbox limits
New campaigns in TechSales default to 40 emails per mailbox per weekday, a setting you can change per workspace, and Sending health flags a mailbox set above 50 a day. TechSales reads each Instantly mailbox's daily limit and what it actually sent every hour; for slow-ramp mailboxes it counts what they can send now, based on the best day of the last seven. The AI SDR uses that capacity to decide when to prepare the next list, and Sending health in Reports checks every mailbox's bounce rate and warm-up score every six hours.
Frequently asked questions
- Can I send 500 cold emails a day from one Gmail account?
- The technical limit allows it, but a single mailbox at that volume of unsolicited email is very likely to see complaints, bounces and throttling. Spread volume over more mailboxes and domains.
- Do the rules change above 5,000 emails a day?
- Yes. Gmail and Yahoo treat senders of about 5,000 or more messages a day as bulk senders, who must have SPF, DKIM and DMARC and one-click unsubscribe for marketing mail. Outlook.com applies similar requirements from May 2025.
- Should I count follow-ups?
- Yes. Every message sent counts towards a mailbox's volume, first emails and follow-ups alike.
Sources
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