IP Warm-Up: A Step-by-Step Schedule for New Email Senders (2026)
Starting to send email from a new IP address or a new domain is one of the highest-risk moments in email marketing. Send too much too fast, and Gmail, Outlook, and Yahoo will treat you as a spammer before you've had a chance to prove yourself.
IP warm-up is the structured process of gradually building a sending reputation by starting with small volumes to your most engaged subscribers and scaling up over several weeks. Done correctly, it establishes your reputation as a trustworthy sender and sets the foundation for long-term inbox placement above 95%.
This guide gives you the exact schedule, the logic behind it, and what to do when things don't go as planned.
Why IP Warm-Up Is Necessary
Every IP address that sends email has a sending reputation — a score that inbox providers use to decide whether to deliver, filter, or block your emails. A brand-new IP has no reputation at all. To a spam filter, unknown = suspicious.
Gmail, Outlook, and Yahoo deliberately rate-limit and filter emails from new IPs as a protective measure. Even if your content is perfect and your list is clean, a new IP sending 100,000 emails on day one will see the majority land in spam.
Warm-up works because inbox providers watch for consistent signals of trustworthy behaviour:
- Recipients open and read your emails
- Recipients don't mark you as spam
- Your bounce rates are low
- You're sending to real, valid addresses
When these signals accumulate over several weeks, your sending reputation rises — and inbox placement follows.
Who Needs to Warm Up?
You need a warm-up whenever:
- You're starting with a completely new sending IP (dedicated IP)
- You're migrating from one email platform to another (new IP pool)
- Your domain has been inactive for 60+ days
- You've significantly increased your sending volume (e.g. from 10K to 500K/month)
If you're on a shared IP pool (most starter plans), the IP warm-up is partially managed by the ESP. But moving to a dedicated IP always requires full warm-up from scratch.
The IP Warm-Up Schedule
This schedule is for a target volume of 100,000–500,000 emails per month. Adjust proportionally for your target volume.
| Week | Daily Volume | Notes |
|---|---|---|
| 1 | 250–500 | Best engagers only (opened in last 30 days) |
| 2 | 1,000–2,000 | Expand to 60-day engagers |
| 3 | 5,000–10,000 | 90-day engagers |
| 4 | 20,000–40,000 | 180-day engagers |
| 5 | 50,000–80,000 | Full engaged list |
| 6+ | Scale to target | Start including lower-engagement segments |
Migomail's email warm-up calculator generates a custom schedule for your specific target volume automatically.
Segment Your List for Warm-Up — This Is Critical
The order in which you send matters as much as the volume. Inbox providers look at your early sends to establish your reputation. If your first 500 emails get 45% open rates and zero complaints, you're starting from a position of strength. If they get 2% opens and multiple spam complaints, you're in a hole that takes weeks to climb out of.
Warm-up engagement tiers:
- Tier 1 (Week 1): Subscribers who engaged with your email in the last 30 days — most recently active, highest expected engagement
- Tier 2 (Week 2): Last 31–60 days engagement
- Tier 3 (Week 3): Last 61–90 days engagement
- Tier 4 (Week 4+): Last 91–180 days engagement
- Avoid until reputation is established: Subscribers who haven't engaged in 180+ days
Step-by-Step: How to Execute Your Warm-Up
Step 1: Configure Authentication Before Sending a Single Email
Before warming up, confirm:
- SPF record is published and valid
- DKIM is configured and signing outgoing emails
- DMARC is published (start with
p=none) - Google Postmaster Tools is set up and your domain is verified
Sending without authentication during warm-up actively damages your reputation and misses the opportunity to establish a clean record from day one.
Step 2: Set Up Google Postmaster Tools
Google Postmaster Tools is free and shows you:
- Domain reputation (Low / Medium / High / Very High)
- IP reputation
- Spam rate as reported by Gmail users
- Authentication pass rates (DKIM, SPF, DMARC)
Register your sending domain here before your first send. The data starts accumulating from your first email. This is your primary monitoring dashboard during warm-up.
Step 3: Send to Your Best Segment First
Export your 250–500 most recently engaged subscribers. These are people who opened or clicked your email in the last 30 days. Send a high-value, relevant email — not a promotional blast.
Warm-up email ideas:
- A useful newsletter with genuinely interesting content
- A personal note from the founder or marketing lead
- A resource download (guide, checklist) your audience will find valuable
- A re-introduction email if you're migrating from another platform ("We've upgraded our email platform to send you better content")
The goal is maximum engagement. Every open, click, and reply strengthens your reputation.
Step 4: Monitor Daily and Act Quickly
During warm-up, check your deliverability metrics every day:
| Metric | Action Threshold |
|---|---|
| Spam complaint rate | Pause if above 0.05% — investigate immediately |
| Hard bounce rate | Pause if above 1% — clean the segment |
| Gmail spam rate (Postmaster) | Slow down if "Medium" appears, stop if "Low" |
| Open rate | If significantly lower than baseline, check placement with a seed list |
Migomail's deliverability dashboard surfaces these in real time. Set up alerts for anything above threshold.
Step 5: Scale Gradually — Don't Skip Steps
The temptation when warm-up is going well is to accelerate. Resist it. Jumping from 2,000/day to 30,000/day will trigger rate limits and filtering at all major providers.
If your metrics are healthy (spam rate below 0.05%, bounce rate below 0.5%, decent open rates), stick to the schedule. If you see warning signs at any tier, pause and hold that volume for 3–5 more days before progressing.
What to Do When Warm-Up Goes Wrong
Spam rate spike
Stop sending immediately. Check:
- Are you sending to the right segment? (Most common cause)
- Does the email content look spammy?
- Are the subscribers on this segment confirmed opt-ins?
Wait 48–72 hours, then resume at the previous tier's volume with a very small segment of highly engaged subscribers to rebuild the signal.
Sudden drop in inbox placement
Run a seed list test (send to test addresses at Gmail, Outlook, Yahoo) to confirm whether the issue is provider-specific. Check:
- Postmaster Tools for Gmail domain reputation
- Whether your sending IP has appeared on a blacklist
- Whether DKIM or SPF has stopped passing (DNS propagation issues)
Outlook filtering aggressively
Microsoft's filters are the strictest in the industry. During warm-up, Outlook often filters new IPs more aggressively than Gmail. Register your IPs with Microsoft SNDS and use their Junk Email Reporting Program. Monitor Outlook-specific placement separately from Gmail.
Frequently Asked Questions
How long does IP warm-up take?
For volumes under 50,000 emails/month, a basic warm-up takes 3–4 weeks. For volumes of 250,000+/month, allow 6–8 weeks for full warm-up to target volume. The timeline depends on how consistently your warm-up sends perform — strong engagement accelerates reputation building.
Do I need to warm up if I'm on a shared IP pool?
On a shared IP pool (standard plans at most ESPs), the IP reputation is managed by the provider and warmed up across all users. You still need to warm up your sending domain reputation — the domain warm-up follows similar principles but is managed through consistent engagement over time rather than a structured volume ramp.
Can I warm up multiple domains simultaneously?
Yes, but treat each domain as an independent warm-up. Do not mix them in the same IP pool during warm-up — each domain needs to build its own reputation independently before being consolidated.
What open rate should I expect during warm-up?
During the first two weeks, sends to your most engaged subscribers should produce open rates of 30–50% or higher. As you expand to lower-engagement tiers, rates will naturally decline. The key metric is not open rate — it's complaint rate and bounce rate. Keep those below threshold and inbox placement will follow.
Should I use my main domain or a subdomain for warm-up?
Use the exact domain and From address you'll use permanently. Warming up newsletter.migomail.com builds reputation for that subdomain specifically — switching to mail.migomail.com later requires starting over. Consistency in your From address and domain is one of the most underrated factors in long-term deliverability.