How long does it take to warm up an IP address for email marketing?
Michael Ko
Co-founder & CEO, Suped
Published 22 May 2025
Updated 19 Aug 2025
7 min read
One of the most common questions in email marketing is how long it takes to warm up an IP address. There's no single, simple answer, because the timeline for IP warming is highly variable. It depends on many factors, including your sending volume, list quality, and audience engagement.
An IP warm-up is essentially a probationary period where Internet Service Providers (ISPs) like Gmail and Outlook.com observe your sending behavior from a new or previously inactive dedicated IP address. They're looking for consistent, responsible sending to ensure you're not a spammer. Building a positive sender reputation is critical for deliverability.
The basics of IP warming
IP warming is the process of gradually increasing the volume of emails sent from a new dedicated IP address over a period of time. This staggered approach helps ISPs recognize your IP as a legitimate sender, not a source of spam. If you try to send a large volume of emails immediately from a cold IP, most ISPs will flag them as suspicious, sending them straight to the spam folder or blocking them entirely. This can lead to your IP being added to an email blacklist or blocklist.
Think of it like building trust. ISPs track various metrics from your sending IP, including bounce rates, spam complaint rates, open rates, and click-through rates. A good warming process demonstrates consistent, healthy sending habits, which in turn builds a positive reputation. Without this, your emails risk significant deliverability issues.
Dedicated IP addresses require warming because their reputation starts from scratch. If you're on a shared IP address, warming is generally not necessary, as the ESP manages the collective reputation. However, for serious email marketers or those sending high volumes, a dedicated IP is often preferred for more control over sender reputation and deliverability.
Factors influencing IP warm-up duration
The length of your IP warm-up period is heavily influenced by several critical factors. Understanding these can help you set realistic expectations and plan your strategy effectively.
List quality and engagement: This is arguably the most crucial factor. Sending to a clean, engaged list with high open and click rates and low bounce and spam complaint rates will significantly accelerate your warm-up. Conversely, a poor-quality list with many inactive or invalid addresses, or high complaint rates, can severely hinder the process and even lead to your IP getting blocklisted.
Sending volume: The higher your target daily sending volume, the longer the warm-up period will generally be. Ramping up to 2 million emails per day will take much longer than warming an IP for 100,000 emails per day. Some senders even warm multiple IPs in a pool to achieve very high volumes faster.
Sending frequency: Consistent daily sending helps build reputation faster than intermittent sending. ISPs prefer to see a steady, predictable volume from a reputable sender.
Recipient domains: Some ISPs are more stringent than others. Microsoft (Outlook, Hotmail) can sometimes be more challenging to warm than Google (Gmail), especially with lower engagement. Diversifying your initial sends across various domains can help distribute risk and build reputation across the board.
It's worth noting that your domain's reputation also plays a role in the overall deliverability of your emails, working in conjunction with your IP reputation. For more details on this, you can review our guide on how to improve domain reputation.
General timelines and best practices
While there's no fixed timeline, most experts agree that a typical IP warm-up takes anywhere from four to eight weeks to achieve optimal deliverability for moderate to high volumes. For very large volumes, it can extend to 10-12 weeks or even longer. Two weeks, as some suggest, is highly ambitious and generally only achievable under very specific, favorable conditions, such as sending to a small, highly engaged list that you've previously mailed with another reputable IP.
A standard warm-up strategy involves sending small batches of emails on day one, then gradually increasing the volume over subsequent days and weeks. The key is to monitor your deliverability metrics closely and adjust your sending volume based on performance. If you see spikes in bounces, complaints, or blocklist (or blacklist) entries, you should slow down your sending.
Typical warm-up schedule
The table below illustrates a sample warm-up schedule for a new dedicated IP aiming for a daily volume of up to 100,000 emails. This is a general guideline, and actual volumes should be adjusted based on real-time feedback from Google Postmaster Tools and other postmaster feedback loops.
Week 1: Start with a few hundred to a couple of thousand emails daily to your most engaged subscribers.
Week 2: Gradually increase daily volume by 10-20%, broadening your audience to include moderately engaged subscribers.
Week 3-4: Continue increasing volume, incorporating more of your active list. Monitor closely for any reputation issues.
Week 5+: Continue to scale up, slowly introducing less engaged segments while maintaining low complaint and bounce rates.
Strategic considerations
To achieve a successful IP warm-up, consider these strategic points:
Segment your list: Start with your most active and engaged subscribers, then gradually expand to less active ones. This sends positive signals to ISPs.
Monitor closely: Pay attention to your deliverability metrics daily. If you notice a drop in performance, reduce your sending volume and investigate the issue.
Send valuable content: Ensure the emails you send during warming are highly relevant and engaging to encourage opens and clicks, and discourage complaints.
Clean your list regularly: Remove inactive subscribers and hard bounces to prevent damage to your sender reputation.
For a more detailed breakdown of this crucial process, explore our comprehensive guide on IP warm-up strategies.
Navigating common challenges
Rushing your IP warm-up is one of the most common mistakes, and it can have severe consequences for your email program. If ISPs detect sudden, high-volume sending from a new IP, they are likely to immediately throttle or block your emails, severely impacting your deliverability. This can lead to your IP being added to a blocklist (or blacklist), making it difficult to reach the inbox even with legitimate emails.
The risks of rushing your IP warm-up
Ignoring the IP warm-up process, or trying to rush it, can lead to several severe problems for your email marketing campaigns.
Spam folder placement: Your emails are highly likely to land in the spam or junk folder, drastically reducing your reach and engagement. Many senders miss this problem because they don't check their inbox placement.
Blocklisting: Your IP address can quickly end up on an email blocklist (or blacklist), which can take weeks or even months to get delisted from. This is a common consequence of aggressive, untrusted sending.
Reputation damage: A poor initial reputation can be very difficult to overcome, leading to long-term deliverability challenges. This affects not just current campaigns, but future ones too.
Maintaining your IP's reputation is an ongoing effort. Even after a successful warm-up, if you have a significant period of inactivity (e.g., more than 30 days without sending), your IP's reputation can 'cool down,' and you might need to go through a mini-warming process again. Regularly sending consistent volumes of valuable content to engaged subscribers is key to long-term success. It's also vital to monitor your blocklist status and other key metrics to ensure sustained inbox placement.
Implementing strong email authentication protocols like SPF, DKIM, and DMARC also plays a crucial role in building and maintaining trust with ISPs, complementing your IP warming efforts. These protocols help verify your identity as a sender and prevent spoofing, further strengthening your sender reputation.
Example IP warm-up schedule
Day
Example Daily Volume
Cumulative Volume
Day 1-3
1,000 - 5,000
1,000 - 5,000
Day 4-7
5,000 - 10,000
6,000 - 15,000
Week 2
10,000 - 20,000
25,000 - 65,000
Week 3
20,000 - 40,000
85,000 - 185,000
Week 4
40,000 - 100,000
225,000 - 485,000
This schedule is a flexible guide. You might need to adjust based on how your audience responds and the specific requirements of the ISPs you're sending to. Always prioritize quality over quantity, especially during the initial stages.
Remember, the goal is not just to send emails, but to get them delivered to the inbox. A well-executed IP warm-up sets the foundation for a strong sender reputation and long-term email marketing success. If you're looking for more guidance on improving your overall deliverability rates, our technical solutions for top-performing senders provides further insights.
Views from the trenches
Best practices
Start with your most engaged subscribers who are likely to open and click your emails.
Send consistent volumes daily during the warm-up period, avoiding large spikes or drops.
Monitor key metrics like open rates, click rates, bounce rates, and spam complaints daily.
Segment your audience by engagement levels and gradually introduce less active contacts.
Prioritize sending valuable, relevant content to encourage positive engagement signals.
Common pitfalls
Sending too much volume too soon can trigger spam filters and damage your IP's reputation.
Ignoring bounce and complaint rates can lead to getting blocklisted (or blacklisted).
Not cleaning your email list of invalid or inactive addresses can hinder warming progress.
Sending to purchased or unengaged lists, which results in low engagement and high complaints.
Inconsistent sending patterns, like sending large volumes then going quiet for days.
Expert tips
If warming multiple IPs, consider pooling them to scale volume more efficiently.
Some ISPs, particularly Microsoft, can be more sensitive to new IP volume than Gmail.
A dedicated IP's reputation cools down after about 30 days of inactivity, requiring re-warming.
Utilize Postmaster Tools from major ISPs to gain insights into your sending reputation.
Ensure your DNS records (SPF, DKIM, DMARC) are correctly configured from day one.
Marketer view
A marketer from Email Geeks says that a two-week warm-up for 2 million emails is ambitious, and it usually takes at least four weeks.
2021-07-12 - Email Geeks
Expert view
An expert from Email Geeks indicates that the required warm-up time significantly depends on factors like data quality, engagement rates, and the breakdown of recipient domains.
2021-07-12 - Email Geeks
The long view on IP warming
There's no single magic number for how long it takes to warm up an IP address for email marketing. It’s a nuanced process influenced by various factors, most notably the quality and engagement of your email list, your target sending volume, and your consistency.
While some highly optimized scenarios might allow for faster warming, a realistic timeframe is typically 4 to 8 weeks, potentially longer for very high volumes or less engaged lists. Patience and vigilant monitoring are your best allies in establishing a strong sender reputation and ensuring your emails consistently reach the inbox.
Gmail and 
Outlook.com observe your sending behavior from a new or previously inactive dedicated IP address. They're looking for consistent, responsible sending to ensure you're not a spammer. Building a positive sender reputation is critical for deliverability.
Microsoft (Outlook, Hotmail) can sometimes be more challenging to warm than 
Google (Gmail), especially with lower engagement. Diversifying your initial sends across various domains can help distribute risk and build reputation across the board.
