How Many Cold Emails Can You Send Per Day Without Hurting Deliverability?
Google Workspace allows up to 2,000 emails a day per user. Microsoft 365 allows far more recipients. Neither number has anything to do with how many cold emails you should send.
Those are platform limits. Inbox placement limits are much lower.
Our working numbers
For warmed-up mailboxes on established domains:
| Item | Safe range |
|---|---|
| Cold emails per mailbox per day | 30 to 50 |
| Mailboxes per domain | 2 to 3 |
| Cold emails per domain per day | 100 to 150 |
| New domain, first 2 weeks | Warm-up only |
You can go higher with excellent lists and strong reply rates. You can also get into trouble below these numbers if your list is poor. Treat them as a starting point, not a promise.
Why per-mailbox limits are low
Filters look at behaviour, not just volume. A real salesperson sends a few dozen external emails a day, gets replies, and has two-way conversations. A mailbox that sends 400 first-touch emails a day and receives almost nothing back doesn't look like a person.
Warm-up traffic and real replies help balance this. That's why we keep warm-up running in the background even after campaigns start.
Working out how many domains you need
Say you want to reach 3,000 new prospects a month with a 3-step sequence.
- Total sends: 3,000 × 3 = 9,000 emails a month
- Working days: about 22, so roughly 410 emails a day
- At 40 per mailbox: about 10 or 11 mailboxes
- At 3 mailboxes per domain: 4 domains
We'd set that up as 4 domains, 12 mailboxes, so you have headroom if one mailbox needs a rest.
Spread the sending out
- Don't send everything at 9 AM. Spread sends across the working day in the recipient's time zone.
- Add random gaps of a few minutes between emails.
- Keep daily volume steady. Sending 50 one day and 0 the next three looks odd.
- Don't send cold email on weekends from a new domain. Low engagement on weekends drags averages down.
Signs you're sending too much
- Gmail placement drops while Outlook stays fine, or the reverse
- Spam rate in Google Postmaster Tools rising above 0.1%
- More
421deferral codes in your logs - Reply rate falling even though copy and targeting haven't changed
When you see these, cut volume per mailbox by half for a week and run a placement test.
What about dedicated IPs?
If you're sending through your own server rather than Google or Microsoft mailboxes, the maths is different. IP warm-up and volume consistency matter more. We cover that in dedicated IP vs shared IP.
Need the domains and mailboxes set up for you? That's exactly what our cold email infrastructure service does, usually within 2 to 3 hours.