Email warmup calculator.
How long your mailboxes need, what a safe week-by-week ramp looks like, and how many mailboxes your daily target actually needs. Nothing you type leaves your browser.
A widely used general guideline, not a HotHawk setting. Change it to match how you send.
Ramp length
3 weeks
before a mailbox is at full volume
Mailboxes needed
5
to hold your daily target
Sustainable a day
150
across the mailboxes you have
Your week-by-week ramp
Per mailbox, and across all the mailboxes you have. A sensible, conservative shape to climb.
| Week | Per mailbox a day | All mailboxes a day | Share of full volume |
|---|
How to read your results
Ramp length is how long before a mailbox is carrying full volume. Three weeks is the baseline, and the calculator adds time for a newer domain or one that has never sent, because a fresh domain is building its own reputation at the same time.
Mailboxes needed divides your daily target by the per-mailbox figure. If it is higher than what you have, the honest answer is to add mailboxes rather than push the ones you have harder. That is the mistake that burns domains: not starting too late, but scaling too fast after starting.
Sustainable a day is what your current mailboxes can carry once fully ramped. If your target is above it, the calculator says so rather than pretending the numbers work.
The ramp table is a shape, not a schedule you have to administer. In HotHawk, warmup ramps up automatically over about three weeks, so there is no schedule to configure. Use the table to plan when your real campaign volume can climb, and watch your bounce rate at each step. A bounce spike means stop and fix the list, not push on.
More detail in the guide to how email warmup works, and the cold email volume calculator works the same arithmetic back from a monthly goal. Last updated 18 October 2026.
Email warmup questions
How long does email warmup take?
Two to four weeks for a mailbox on an established domain, and longer if the domain is new, because the domain is building its own reputation at the same time. In HotHawk, warmup ramps up automatically over about three weeks. The calculator adds weeks for a newer domain or one that has never sent before.
How many emails a day can one mailbox send?
The calculator defaults to 30 a day per mailbox, which is a widely used and deliberately conservative guideline for cold email, not a rule and not a HotHawk setting. You can change it. Scale by adding mailboxes rather than pushing any single one harder, because a mailbox that looks fine at 20 a day can fall over at 200.
Can I warm up an IMAP or SMTP mailbox?
Not in HotHawk. Warmup only covers Google Workspace and Microsoft 365 mailboxes connected with OAuth. A mailbox on cPanel, webmail or a small host, connected over IMAP and SMTP, can send campaigns from HotHawk, but it cannot join the warmup pool. Warmup is only worth anything if the inboxes engaging with you are the kind your prospects use and the providers already trust.
Why does a new domain take longer to warm up?
Because reputation attaches to the domain as well as the mailbox. On an established domain the mailbox inherits some existing trust. On a brand new domain there is no history at all, so you are building both at once and it is worth going slower.
Should I turn warmup off once campaigns start?
No. Leaving it running is what holds the reputation you built, and it lets a mailbox absorb the odd spam complaint without the score dropping. Switching it off once real sending begins is one of the most common ways people quietly lose a mailbox.
Is this calculator accurate?
It is a planning aid, not a guarantee. No tool can predict how a specific provider will treat a specific mailbox, and anyone claiming otherwise is selling something. Treat the output as a sensible, conservative starting shape and watch your bounces as you climb.
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