Can you warm up an IP in a week?

Someone tells you they need a dedicated IP up and running in a week. It sounds doable. After all, how long can it really take to establish a bit of reputation? The honest answer is that a proper IP warmup takes 4 to 6 weeks at minimum, and trying to compress that into seven days is one of the most reliable ways to tank your deliverability before you've even started.

Here's why. When a brand new IP sends email, mailbox providers like Gmail and Outlook have no history to judge you on. No reputation means they treat your mail with suspicion by default. The warmup process exists to build that reputation gradually, by proving your list is clean, your engagement is real, and your sending patterns are predictable. Flood a cold IP with 100,000 emails on day one and you look like a spammer. Because that's exactly what spammers do.

A realistic week-by-week schedule looks something like this:

• Week 1: Send to your absolute best subscribers only. We're talking 500 to 1,000 emails per day, maximum. These should be people who open everything you send. Your engagement rates here set the tone for everything that follows.
• Week 2: If week one went cleanly (more on that below), you can double or triple your volume. Still keep it to your most engaged segment. Watch your numbers closely before touching that dial again.
• Week 3-4: Gradually expand to your broader active list. You can start approaching 10,000 to 20,000 per day depending on your list size and what the metrics are showing.
• Week 5-6: If everything has held steady, you can push toward your full sending volume. Don't rush the final stretch. This is where a lot of senders get impatient and undo weeks of good work.

The metrics you need to watch every single day during warmup are your bounce rate, your spam complaint rate, and your open rate. Bounce rate above 2% is a red flag. Complaint rate above 0.1% is a serious warning sign (Google's threshold is 0.1%, and once you're above 0.08% you should already be pulling back). If your open rates are dropping week over week while you're scaling up, that's the warmup telling you to slow down, not speed up.

There's also the question of what you send during warmup. This isn't the time for your riskiest campaigns. Send your best content, your most relevant offers, the emails that historically get the most opens and clicks. You're trying to collect positive signals, not test subject line tricks. Replies count too. An email that someone actually writes back to is a strong trust signal for mailbox providers.

Still one more thing worth noting. Warmup applies to dedicated IPs, but the domain behind the IP also builds its own reputation. Even if you could warm an IP in a week, your domain reputation takes time to establish independently. Skipping warmup doesn't just hurt the IP. It can leave a stain on the domain that outlasts any IP swap.

If you're staring down a hard deadline and genuinely need to send at scale sooner than 6 weeks, consider using a shared IP pool through your ESP for the initial burst while your dedicated IP warms in parallel. Not ideal, but better than burning a fresh IP on your largest send of the quarter.

Not sure where your warmup stands right now? Our SOS hotline is free, and we can take a look at what you're working with.