How many cold emails can you send a day before you land in spam?
About 30 to 50 per mailbox, per day, and only after a two-week warm-up. Gmail technically lets you send 2,000 a day. Try that with cold email and almost all of it will go to spam.
Why the real limit is so low
Google's and Microsoft's filters don't just count emails. They watch how people react. A new mailbox suddenly sending hundreds of emails to strangers, most of whom never open or reply, looks exactly like a spammer. Once a mailbox or domain gets that reputation, even your normal emails start landing in junk.
Since 2024, Google has also required bulk senders to keep spam complaints under 0.3% and to have SPF, DKIM and DMARC set up on their domain.
The safe ramp for a new mailbox
| Week | Cold emails a day | What else |
|---|---|---|
| 1 to 2 | 0 | Warm-up only: 10 to 20 normal emails a day that get replies |
| 3 | 15 to 20 | Keep warm-up running |
| 4 | 25 to 30 | Watch bounces; stop if they pass 3% |
| 5 onwards | 30 to 50 | This is the ceiling. It doesn't keep rising. |
So how do people send thousands a month?
More mailboxes, not more email per mailbox:
- Buy a couple of domains that look like yours, so your main domain is never at risk.
- Put two or three mailboxes on each domain.
- Warm every mailbox for two weeks, then send 30 to 50 a day from each.
Ten mailboxes at 40 a day is 400 emails a day, roughly 8,000 a month, and none of them is pushed hard.
Five things that keep you out of spam
- Plain text. No images, no fancy HTML, no attachments in the first email.
- Turn off open tracking. The tracking pixel is a common spam signal. Judge campaigns on replies instead.
- Verify your list. Keep bounces under 2%.
- Write like a person. Short, specific, one question.
- Send at human times. Weekday mornings, spread out.