How to Warm Up a New Email Domain: A Day-by-Day Volume Schedule You Can Defend

A brand-new domain has no sending history, so mailbox providers have nothing to judge it by except how you behave in the first weeks. Warm-up is the practice of building that history on purpose: small, steady, wanted volume that grows only while the numbers stay clean. There is no official universal schedule, so this guide separates what providers state from what is a reasonable plan, and shows the arithmetic behind each step.

What warm-up actually is (and is not)

Warm-up does not trick filters. Providers watch how recipients react to your mail: opens and replies on one side, spam reports and bounces on the other. A gradual ramp gives them a representative sample before you send at full size, and gives you time to find problems while they are still small. Twilio SendGrid says as much about its own process: a slow warm-up lets you spot and fix anomalies early.

It applies to two things that people mix up. A new IP address has no reputation, and a new domain has none either, even on an IP with a good record. If you move to a new sending domain, treat it as new. Dedicated infrastructure and a fresh domain both need a ramp; mail that your provider sends from a well-used shared pool carries the pool's reputation, so the domain still needs steady, clean use but a hard ramp matters less.

Step zero: authenticate before the first message

Do not send a single warm-up message until the basics pass, because warm-up volume sent unauthenticated is wasted reputation. Requirements differ by provider and by volume:

Provider	Applies to	Authentication stated
Gmail	All senders; bulk senders (close to 5,000 messages a day to personal Gmail accounts)	SPF or DKIM for everyone; SPF, DKIM and DMARC for bulk senders
Yahoo	All senders; bulk senders	SPF or DKIM at minimum; both plus a DMARC policy of at least p=none for bulk senders
Outlook.com	High-volume senders (5,000 or more messages using the same 5322.From domain)	SPF and DKIM checks pass, DMARC record published, and at least one of SPF or DKIM aligned

Google also states that bulk-sender status has no expiration date, and a new domain is one that has not sent more than 5,000 emails a day to personal Gmail accounts since January 1, 2024. A domain that starts small today can cross 5,000 later, so set up all three records now rather than when you grow. Check them with the tool below.

🛡️SPF, DKIM & DMARC CheckerRecursive SPF with the 10-lookup limit, DKIM keys and DMARC policyOpen the tool →

The sourced rules, in one place

• Google: start with a low sending volume to engaged users and increase it slowly; send at a consistent rate and avoid bursts; avoid sudden spikes if you have no history of large volumes.
• Twilio SendGrid (manual guideline): no more than 50 emails on a new IP's first day, then double the volume every consecutive day you send until you reach your planned maximum.
• Twilio SendGrid (automated): an hourly cap that starts at 20 emails an hour on day 0 and rises to 1,000 an hour on day 12; the IP leaves automated warm-up after day 41, and an IP that has sent nothing for more than 30 days should be warmed again.
• Yahoo: send relevant mail to an active, engaged audience and keep the spam rate below 0.3%.

Notice what is missing: none of these pages publishes a daily number that all providers accept. The 50-and-double figure is one sender's guideline for its own platform, so use it as a starting shape, not a rule of the mailbox providers.

A schedule you can adapt: 50, then double

Take a target of 20,000 messages a day. Starting at 50 and doubling each sending day gives this plan, capped at the target:

Day	Messages	Running total	Who to send to
1	50	50	People who replied or clicked recently
2	100	150	Same group, then recent opens
3	200	350	Recent clickers and buyers
4	400	750	Active in the last 30 days
5	800	1,550	Active in the last 30 days
6	1,600	3,150	Active in the last 60 days
7	3,200	6,350	Active in the last 60 days
8	6,400	12,750	Active in the last 90 days
9	12,800	25,550	Active in the last 90 days
10	20,000 (target)	45,550	Full list, oldest segments last

The sum before the final day is 50 × (2⁹ − 1) = 25,550. The engagement column is our suggestion, built on Google and Yahoo asking for engaged audiences; the providers do not publish segment ages. If your target is 2,000 a day, the same shape reaches it on day 7 (50, 100, 200, 400, 800, 1,600 and then 2,000), so smaller senders finish within a week.

Doubling is aggressive for a cold start. Many teams hold each step for two or three days when the audience is small or the list is older, and that is fine: Google asks for a consistent rate, and nothing requires you to double every single day.

What SendGrid's hourly table implies

The automated schedule is a ceiling per hour, not a quota, so read it as the fastest pace the platform allows. Multiply an hourly figure by 24 to get the most a day could carry.

Warm-up age (days)	Hourly limit	Ceiling per 24 hours
0	20	480
3	55	1,320
7	211	5,064
12	1,000	24,000
14	2,222	53,328

By day 7 the cap already allows more than 5,000 messages a day, which is the point where Gmail and Outlook.com start treating you as a bulk or high-volume sender. That is another reason to finish authentication first.

The spam-rate math at tiny volumes

Google asks senders to keep the user-reported spam rate in Postmaster Tools below 0.10% and to avoid ever reaching 0.30%. Those percentages are unforgiving on day one. With 50 messages, a single spam report is 1 / 50 = 2%. At 100 messages it is 1%. To stay under 0.10% you need more than 1,000 messages for every report, and to stay under 0.30% about 333.

Messages in the day	One report equals	Reports allowed under 0.10%
50	2.00%	0
800	0.125%	0
1,600	0.0625%	1
12,800	0.0078%	12

Postmaster Tools hides days with too little volume, so you will not see these early spikes in the dashboard, and Google says the rate is based on mail delivered to the inbox, not on all messages. The practical lesson: during the first hundreds of messages, a single complaint teaches more than a percentage does. Send only to people who asked for the mail, and check complaints yourself from your sending platform. The bounce and complaint rates guide covers the formulas.

📊Email Metrics CalculatorDelivery, open, click, bounce and complaint rates with 95% confidence intervals and consistency warningsOpen the tool →

When to pause or slow the ramp

• Hard bounce rate climbs. Stop adding new segments, clean the list and resume at the last good step. Run the list through the cleaner below first.
• Spam rate approaches 0.10% or any complaint appears in a small batch. Hold the volume for a few days and review who is receiving the mail.
• Rejections or throttling appear. A temporary deferral means the provider asks you to slow down; resume at a lower step instead of retrying in bursts.
• You skipped days. SendGrid says to re-warm an IP that has sent no mail for more than 30 days. A gap of a week on a new domain is a reason to repeat a step, not jump ahead.

🧹Email List CleanerRemove duplicates and invalid addresses, fix typos and split by providerOpen the tool →

Mistakes that undo a warm-up

• Sending the whole list on day two. A spike with no history is exactly what Google tells senders to avoid.
• Warming with purchased or old contacts. Yahoo says not to purchase lists; unknown addresses produce bounces and traps. Confirm signups, ideally with double opt-in.
• Sending in bursts. One large batch a week looks different from a steady daily stream. Spread the send across the day.
• Changing too many things at once. A new template, new offer and new volume together make any problem impossible to trace.
• Using warm-up as a trick. Messages sent only to look engaged do not help; the point is wanted mail that recipients actually read.

Once you pass 5,000 messages a day, review the full Gmail and Yahoo bulk sender requirements and set up Postmaster Tools so you can read your spam rate directly.

Frequently asked questions

How long does it take to warm up a new email domain?

There is no official duration. Following a 50-and-double pattern, a 20,000-a-day target is reached on day 10 and a 2,000-a-day target on day 7. SendGrid's automated IP schedule runs 41 days, and holding steps for a few days is normal when the list is small or older.

How many emails should I send on the first day?

Twilio SendGrid recommends no more than 50 emails on the first day for a new IP address, and Google asks new senders to start with a low volume to engaged users.

Do I need to warm up a new domain if I use a shared IP from my email service?

The domain still has no history, so send steadily and to engaged people, but a hard ramp matters most on dedicated IPs. Check your provider's own onboarding advice, because shared pools differ.

What spam rate should I keep during warm-up?

Google asks senders to keep the user-reported spam rate below 0.10% and never reach 0.30%; Yahoo asks for below 0.3%. At 50 messages, one report is already 2%, so send only to people who requested the mail.

Can I skip days during warm-up?

You can, but keep the rate consistent. SendGrid says to warm an IP again after more than 30 days with no mail; after shorter gaps, repeat the last step before increasing.

References & further reading

1. Google Workspace Admin Help — Email sender guidelines
2. Google Workspace Admin Help — Email sender guidelines FAQ
3. Twilio SendGrid — Warm up an IP address
4. Twilio SendGrid — IP warmup for Marketing Campaigns
5. Microsoft Support — Fix NDR error 550 5.7.515 in Outlook.com
6. Yahoo Sender Hub — Best practices