Question 1

How many weeks should I set the ramp to?

Accepted Answer

Long enough that bounce and complaint rates stay flat while volume rises, which is a condition rather than a number. No mailbox provider publishes a warmup schedule, so any specific week count is someone's heuristic rather than vendor guidance; what providers publish are ceilings and reputation thresholds. The six-week default this calculator opens with is a starting shape, not a recommendation. Set the length that leaves you room to hold volume where it is the moment the numbers move, and treat the ramp as a plan to pause rather than a schedule to force. On whether warming helps at all, see does email warmup work.

Question 2

How many emails can I send per day from Google Workspace?

Accepted Answer

Google documents a daily sending limit of 2,000 messages per user account, dropping to 500 on trial accounts. Separate limits apply to recipients: 10,000 total recipients per day, 3,000 external recipients per day, and 2,000 recipients on a single message with a maximum of 500 external. These are hard limits enforced by the platform, not reputation thresholds, and no amount of warming increases them.

Question 3

How many emails can I send per day from Microsoft 365?

Accepted Answer

Exchange Online enforces a recipient rate limit of 10,000 recipients per mailbox in a rolling 24-hour window, which caps single-recipient messages at the same figure. Recipients on one message are customizable up to 1,000. There is also a message rate limit of 30 messages per minute per mailbox, so a large daily total has to be spread through the day rather than sent in one burst. Microsoft additionally applies a tenant-level external recipient limit that scales with your licence count.

Question 4

Where does this calculator's curve come from?

Accepted Answer

Arithmetic on the two volumes you enter, and nothing else. Steady percentage growth compounds the same percentage each sending day between your start and your target; equal steps adds the same number of messages every day. Neither shape is vendor guidance, because no provider publishes one. Google's sender guidelines tell you to increase volume gradually and to reduce it when messages start bouncing or being deferred, without day-by-day numbers, and Microsoft publishes limits rather than a ramp. That gap is why warmup schedules vary so much between tools: they are all estimates. What you can hold anyone to are the published figures, which is why this calculator checks your target against those and labels the curve itself as arithmetic. For how the published guidance reads in full, see the email warmup schedule guide.

Question 5

What should I watch while warming up?

Accepted Answer

Complaint rate first, because it has real published thresholds: Google requires bulk senders to stay under 0.3% and recommends under 0.10%, and Yahoo publishes the same 0.3% ceiling. Then hard bounces, which signal list quality and are the rate Amazon SES enforces against on your own sending account. Then engagement, since providers weigh whether people open and reply. If any of these move the wrong way, hold volume where it is rather than continuing up the ramp.

Question 6

Do I need to warm up a new domain, a new IP, or both?

Accepted Answer

Both carry reputation, and which one dominates depends on how you send. On shared infrastructure like Google Workspace or Microsoft 365 you do not control the IP at all, so domain reputation is the thing you are building. On a dedicated IP through an ESP or your own server, the IP has its own history and needs its own ramp. A new domain on a new dedicated IP is the slowest case, because neither has a track record.

Question 7

Does a warmup replace email authentication?

Accepted Answer

No, and warming an unauthenticated domain works against you. Google and Yahoo require SPF, DKIM and DMARC from senders of 5,000 or more messages a day. Volume without authentication builds a reputation on an identity mail providers cannot verify. Publish the records first, confirm they pass, then start the ramp.

Question 8

Can warmup services or reply networks help?

Accepted Answer

Automated warmup networks send mail between accounts and mark it as important to simulate engagement. Mailbox providers describe artificial engagement as something they detect and act against, and Google's guidelines are explicit that senders should send only to people who asked for the mail. The safer ramp is real mail to real recipients who expect it, which is what this calculator plans for.

Week	Per day (start → end)	Sending days	Week total
1	20 → 34	5	133
2	39 → 67	5	261
3	77 → 132	5	514
4	151 → 260	5	1,009
5	297 → 509	5	1,980
6	583 → 1,000	5	3,888

Email Warmup Calculator

Your ramp

Your schedule

The limits this plan is checked against

What decides whether the ramp works

Sources

What is an email warmup calculator?