Email warmup schedule calculator

Email warmup works by gradually increasing the number of emails sent from a new mailbox or domain every day. It establishes positive sending patterns with internet service providers (such as Google Workspace and Microsoft 365), building sender domain reputation and inbox placement before running full-scale cold email campaigns.

Warmup means raising the number of emails a new mailbox or domain sends gradually instead of starting at full volume. Mailbox providers judge a sender partly on its history, and a new address that suddenly sends hundreds of messages looks like a spammer. A slow ramp gives the provider time to see normal behaviour.

No. This calculator creates a day-by-day sending plan from the values you enter. It does not connect to your mailbox, exchange messages or send emails. Export the schedule as CSV and review it against your provider limits and actual bounce and complaint rates.

Your provider's hard limit is the ceiling, not the target. Google, for example, publishes a daily sending limit for Workspace accounts that is far above what most cold email teams send from one mailbox. Many teams keep each mailbox well below the limit and add more mailboxes instead, which spreads the risk if one runs into trouble.

Long enough that you are not making big jumps. With the example values in the tool, three mailboxes reach their cap of 40 a day on day 19. A smaller daily increase takes longer and is gentler; a bigger one is faster but riskier.

This tool plans the volume you send yourself. Warmup services also exchange emails between their users' inboxes to build engagement. Either way, the fundamentals matter more: SPF, DKIM and DMARC set up correctly, a list of real addresses that do not bounce, and messages people actually want to answer.

Bounces and spam complaints. Google asks senders to keep the spam rate reported in Postmaster Tools below 0.3%. If bounces or complaints rise, hold the volume where it is or step it back, and check the list before you send more.