New mailboxes start with no sending history. Warm-up tools exchange low-volume email between mailboxes so yours has some before you ask a stranger for anything. Inbox providers don’t publish warm-up rules, so the schedule below is a practitioner default, not an official requirement.
What’s a good warm-up schedule?
| Week | Warm-up a day | Cold a day | Goal |
|---|---|---|---|
| Before | 0 | 0 | Domain bought early; SPF, DKIM, DMARC passing; profile photo and signature set |
| 1–3 | 5, rising to 20 | 0 | Test emails land in the inbox |
| 4 | About 15 | 10 | First small campaign to your best segment |
| 5 | About 10–15 | 15–20 | Bounces under 1%, no angry replies |
| 6+ | About 10 | 20–25 | Steady state; grow by adding mailboxes |
Which warm-up settings matter?
- Daily increase: 1–2 emails a day. No jumps.
- Gap between sends: randomised, roughly 5–15 minutes.
- Daily volume: let it vary a little from day to day; identical totals look automated.
- New campaigns: turn on “slow ramp” even on old mailboxes.
- Accounts: real seats in your own tenant. Free, student and resold accounts were early casualties of Google’s late-2025 suspensions.1
Should warm-up stay on after launch?
| One camp says | The other says | Default |
|---|---|---|
| Keep it on forever; it keeps positive engagement flowing | Providers can spot engineered engagement; switch it off on aged mailboxes | Low and steady, about 10 a day, from a reputable pool |
Nobody has published clean evidence either way. Whatever you choose, judge mailboxes by their reply rates, not by the warm-up tool’s “health score”, which only measures warm-up.
How do I know a mailbox is ready?
- A test email to Gmail shows SPF, DKIM and DMARC all PASS under Show original. See the DNS guide.
- Test emails land in the inbox, not spam. Treat seed tests as a smoke alarm, not proof.
- The domain is at least 30 days old and the mailbox has had 3–4 weeks of warm-up.
Google Postmaster Tools only shows data once you send meaningful volume to personal Gmail, and its reputation dashboards were retired in 2025,2 so most small senders will see little there during warm-up.
Common questions
How long should I warm up a new domain for cold email?
Three to four weeks per mailbox, on a domain at least 30 days old, before the first cold email. Then start at 10 cold emails a day and rise by 1–2 a day to 15–25.
Should I keep email warm-up on forever?
It’s debated. Some experienced senders keep it on permanently; others switch it off on aged mailboxes because providers can spot engineered engagement. The playbook’s default is a low, steady volume of about 10 warm-up emails a day from a reputable pool, judging mailboxes by reply rate rather than health score.
Can I skip warm-up if I buy aged or pre-warmed mailboxes?
They save time, but vet them: ask whether they’re real Google or Microsoft seats in your own tenant, whether you can move them between sending tools, and what happens when one burns. Still start at 10 cold emails a day.
Keep reading
Sources
- Salesforge: Google’s cold-email mailbox suspensions, October 2025 (vendor estimate). salesforge.beehiiv.com
- Suped: Postmaster Tools reputation dashboards discontinued. suped.com