Email warmup calculator

What the warmup calculator does

Enter the provider, the age of the inbox and the daily cold volume you want to reach. The calculator builds a day-by-day schedule of warmup emails and cold sends, shows how many weeks it takes to reach full volume, and exports the schedule as a CSV.

How warmup works

A new inbox has no sending history, so filters don't know whether to trust it. Warmup builds that history. The inbox exchanges a small number of emails a day with other real inboxes that open them, reply and move them out of spam, while cold volume starts low and rises in steps.

The schedule follows a ramp of two to four weeks. Older inboxes on domains with a clean history ramp faster. A domain registered last week starts at the slow end.

How to follow the schedule

• Raise cold sends on the days the schedule shows, not all at once.
• Keep warmup running after you reach full volume. It adds steady positive engagement next to the cold mail.
• If bounces, spam placement or block messages rise, hold the volume flat for a few days instead of pushing through.
• Warm every inbox on a domain together, so the domain builds one consistent history.

Why it matters for cold email

Skipping warmup is a quick way to burn a new domain. A fresh inbox that sends 50 cold emails on its first day looks like a throwaway spam account, and filters treat it like one. A burned domain doesn't recover quickly, so waiting three weeks costs less than buying new domains.

In Ken, warmup keeps running while an inbox is in live campaigns, and pauses once it has been out of campaigns for 30 days.