Guide
How to warm up the Gmail inbox you already use
Your mailbox already has a history, which helps. Cold email is a new kind of mail from it, so it still needs a slow start.
Short answer
Start low and rise slowly, as Google advises: "Start with a low sending volume to engaged users, and slowly increase the volume over time" [1]. In practice: about 20 cold emails a day at first, 10 more each sending day, never above 50, sent every working day rather than in weekly batches [2]. If bounces appear, go back down [4].
Why an existing inbox still needs warming up
A mailbox you have used for years has a reputation built on ordinary mail: replies, threads, people you know. Cold email is different mail, to people who have never heard from you. Google's advice to bulk senders who change what they send is the same idea: "If you change the format of your bulk emails, gradually increase the sending volume of messages with the new format" [3]. The history helps; it does not make a sudden 50 a day look normal.
A schedule
| Sending day | Cold emails, follow-ups included |
|---|---|
| 1 | 20 |
| 2 | 30 |
| 3 | 40 |
| 4 onward | 50, and no higher |
| Personal @gmail.com address | 20, and no higher |
Count sending days, not calendar days: a week off does not earn a higher limit. Send every working day if you can; Google notes that "You can increase the sending volume more quickly when you send daily instead of weekly" [2].
Who to write to first
Google says to start "to engaged users" [1]. For cold email the nearest thing is the people most likely to reply: organisations whose site gives you a real reason to write, at addresses they publish themselves. Save the long shots for later.
When to slow down
- Bounces. "If messages start bouncing or start being deferred, reduce the sending volume until the SMTP error rate decreases" [4]. Three bounces in thirty first emails is already 10%.
- Spam reports. Keep them below 0.3% [5], which at this volume means almost none.
- Refusals. Any 550 5.7.1 from Gmail is a reason to stop and read; see what each version means.
What about warm-up services?
Some tools trade emails between thousands of mailboxes that open and reply to each other automatically. We do not use them: the replies come from machines, not people, so they say nothing about whether your real emails are wanted. A slow start with real, well-chosen recipients is slower and honest, and it is the approach Google describes.
How Honest Intros does it
Honest Intros applies this schedule to every mailbox automatically: 20 a day on the first sending day, 10 more each sending day, at most 50, follow-ups included, and 20 for a personal Gmail address. If bounces trip its brake, new first emails pause and the daily cap is halved when sending resumes.
Questions
How long does it take to warm up a Gmail inbox for cold email?
With a schedule of 20, 30, 40 and then 50 a day, four sending days to reach the ceiling. Keep watching bounces and replies after that; warm-up does not end the need for care.
Do I need to warm up an old Gmail account?
Yes, a little. The history helps, but cold email is a new kind of mail from that account. Google advises bulk senders to increase a new kind of email gradually, and the same caution suits one person.
How many cold emails a day from a new Gmail account?
Start at about 20 a day. A personal @gmail.com address has no domain reputation of its own to lean on, so we keep it at 20.
Are automated warm-up tools safe?
They produce engagement from machines rather than people. Google's advice is to start with engaged recipients and increase slowly, which a warm-up network does not replace.
See what it would write for you
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