IP Warmup: The Complete Guide with Day-by-Day Schedule (2026)

Why IP Warmup Exists

A new dedicated IP has no sending history. Mailbox providers (Gmail, Outlook, Yahoo) have no data about whether this IP sends wanted or unwanted mail.

When they see a new IP suddenly sending thousands of emails, the default assumption is spam. The IP gets throttled, deferred, or blocked.

Warmup solves this by slowly introducing your IP with small volumes of email to engaged recipients, building a positive reputation over time.

The Day-by-Day Warmup Schedule

This schedule targets a final daily volume of 50,000 emails. Adjust proportionally for your target volume.

Day	Daily Volume	Notes
1	50	Most engaged recipients only
2	100
3	200
4	400	Check: bounce rate < 3%, complaints < 0.1%
5	600
6	1,000
7	1,500	Week 1 checkpoint: review all metrics
8	2,000
9	3,000
10	4,000
11	5,000	Check Google Postmaster Tools for reputation
12	7,000
13	9,000
14	12,000	Week 2 checkpoint
15-17	15,000
18-20	20,000	Check: domain reputation should be Medium or High
21	25,000	Week 3 checkpoint
22-24	30,000
25-27	35,000
28	40,000	Week 4 checkpoint
29-35	45,000-50,000	Full volume if metrics are clean

Monitoring Checkpoints

At each checkpoint, verify:

• Bounce rate: Must stay below 3%. Hard bounces above 5% = stop and clean your list.
• Spam complaint rate: Must stay below 0.1%. Above 0.3% = stop immediately.
• Deferral rate: Some deferrals are normal during warmup. Sustained high deferrals = slow down.
• Google Postmaster Tools: Domain reputation should progress from None → Low → Medium → High.
• Inbox placement: Test with GlockApps or similar. Inbox rate should improve as warmup progresses.

Rules for Successful Warmup

Send to engaged recipients first. Start with people who opened or clicked in the last 30 days. Their positive engagement signals build reputation fastest.

Be consistent. Send every day during warmup. Gaps reset momentum.

Don't spike volume. Never increase more than 50% day-over-day. If metrics deteriorate, hold or reduce volume.

Mix content types. If you send both transactional and marketing, include both during warmup. Don't warm up with only transactional then switch to marketing — the content shift confuses filters.

Don't send to cold lists. Purchased lists, scraped lists, or lists that haven't been mailed in months will destroy a warming IP. Clean your list before starting warmup.

When Warmup Fails: Recovery

If you see:

• Bounce rate > 5%: Stop. Clean list. Restart in 48 hours at 50% of your last successful volume.
• Complaint rate > 0.3%: Stop. Review your list source and content. Restart with a smaller, more engaged segment.
• Blacklisted: Stop. Request delisting from all lists. Wait for removal confirmation. Restart warmup from Day 1.
• All deferred/throttled by one provider: That provider has flagged you. Reduce volume to that provider specifically. Continue normally with others.

Practitioner note: The #1 warmup mistake: sending to your full list on Day 1 because "we can't wait 4 weeks." I've seen this destroy brand-new dedicated IPs within 48 hours. The IP then takes longer to recover than the warmup would have taken.

Practitioner note: If you're migrating ESPs (e.g., Mailchimp to Klaviyo) and getting a new dedicated IP, overlap your sending. Keep the old ESP active during warmup and gradually shift volume. Don't flip a switch.

Practitioner note: AWS SES has its own warmup considerations — it starts in sandbox mode and has sending rate limits even after production approval. Plan for SES-specific warmup on top of standard IP warmup.

If the warmup process feels like too much to manage alongside running your business, schedule a consultation — I manage IP warmup programs end-to-end, including monitoring, adjustments, and escalation handling.

Sources

• Google: IP Warmup Recommendations
• SendGrid: IP Warmup Guide
• Mailgun: IP Warming

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v1.0 · March 2026