What is the optimal email volume per IP address and what factors influence it?
Matthew Whittaker
Co-founder & CTO, Suped
Published 29 Jun 2025
Updated 19 Aug 2025
8 min read
One of the most frequent questions I encounter in email deliverability is about the optimal email volume per IP address. It's a critical aspect, yet there isn't a simple, universal answer. The truth is, optimal volume is highly dependent on a variety of factors, and what works for one sender might not work for another. Understanding these nuances is key to maintaining a strong sender reputation and ensuring your messages consistently reach the inbox.
When you send emails, mailbox providers (like Gmail and Outlook) scrutinize your sending IP's behavior. They track everything from spam complaints to open rates, bounce rates, and crucially, your sending volume and consistency. Sending too much too quickly, or having erratic sending patterns, can signal suspicious activity, leading to throttling, deferrals, or worse, placement on a blocklist (or blacklist, if you prefer that term).
The role of IP reputation and IP warming
IP warming is a foundational concept here. If you're using a new IP address, you can't just unleash millions of emails on day one. You need to gradually increase your sending volume over several weeks to build a positive reputation with ISPs. This process tells mailbox providers that you are a legitimate sender. Neglecting to warm up an IP, or dramatically changing your sending volume without warning, can severely damage your deliverability. I always emphasize that consistency is more important than absolute volume when building and maintaining IP reputation, as discussed in detail when looking at how email volume and fluctuations impact deliverability.
There are general recommendations for warming up an IP. For instance, Microsoft's Dynamics 365 documentation outlines a gradual increase from a few thousand emails daily to potentially hundreds of thousands. However, this is a guideline, not a strict rule. The specific ramp-up schedule depends heavily on your list quality, engagement rates, and the types of emails you're sending. You can find more specific advice on best practices for IP warming strategy and email volume scaling in our knowledge base.
In essence, the optimal volume isn't a fixed number but a dynamic range determined by your sending habits and recipient engagement. If your email reputation is strong, you might handle higher volumes without issue. If it's weak, even moderate volumes could lead to deliverability problems.
IP warming
Start with low volumes of highly engaged contacts.
Gradually increase sending volume over several days or weeks.
Consistent sending
Maintain a regular sending schedule and consistent volume.
Avoid sudden spikes or drops in volume.
Shared versus dedicated IPs
Your choice between a shared IP and a dedicated IP also plays a significant role in determining your optimal sending volume. Shared IPs are used by multiple senders, meaning their collective behavior influences the IP's reputation. This can be beneficial for lower volume senders, as they benefit from the established reputation of the shared pool, but also carries the risk of being affected by other senders' poor practices. For managing volume for larger campaigns with a shared IP, careful list segmentation and engagement monitoring are crucial.
A dedicated IP, on the other hand, gives you complete control over your sending reputation. However, this means you are solely responsible for building and maintaining that reputation. This option is typically recommended for senders with high and consistent volumes. If you send below a certain threshold, a dedicated IP might not be justified or even beneficial, as mailbox providers might not have enough data to form a reliable reputation for your IP.
For dedicated IPs, common guidelines suggest a minimum monthly volume of 100,000 to 200,000 emails, or around 5,000 emails per day, to provide enough data for mailbox providers to build a consistent reputation. Going much higher, into the millions per day, requires careful management and excellent sending practices. My advice is to consider a dedicated IP if your monthly volume consistently exceeds 250,000 emails and you have strong engagement.
Shared IP addresses
Pros: Cost-effective for low-to-medium volume senders.
Benefit from collective positive reputation if the pool is well-managed.
Cons: Reputation can be affected by other senders in the pool.
Less control over your own sending performance.
Dedicated IP addresses
Pros: Full control over your IP reputation.
Ideal for high, consistent email volumes.
Cons: Requires careful IP warming and ongoing monitoring.
Not suitable for low or inconsistent sending volumes.
Factors beyond volume
Beyond the sheer number of emails, several critical factors influence what an optimal email volume per IP address truly is:
Engagement rates: This is paramount. High opens, clicks, and replies signal to ISPs that your emails are valued. Low engagement, conversely, is a red flag. If your engagement dips, even a moderate volume can look suspicious. You need to keep an eye on your deliverability metrics to understand if your volume is appropriate for your audience.
Spam complaint rates: High complaint rates are a quick path to blacklists (or blocklists). Even a small percentage of complaints can severely damage your IP reputation. This often indicates issues with list quality or content relevance.
Bounce rates: High hard bounce rates (invalid email addresses) indicate a poor quality list. This signals to ISPs that you might not be maintaining your recipient list properly, which can negatively impact your sender reputation. A high volume of bounces can lead to your IP being placed on a blocklist.
Content quality: Spammy content, excessive links, or misleading subject lines can trigger spam filters, regardless of your sending volume. Make sure your emails are valuable and relevant to your subscribers.
These factors collectively inform mailbox providers' decisions. If you have low engagement or high complaints, even a modest email volume might be too much for your IP. Conversely, a highly engaged list can support much higher volumes.
Monitoring and adapting your sending volume
To gauge your true optimal volume, you need to constantly monitor your deliverability metrics. Your email service provider (ESP) typically provides dashboards with data on bounces, complaints, and engagement. Pay close attention to these indicators, as they are real-time feedback from mailbox providers.
Another powerful tool is Google Postmaster Tools, which offers insights into your IP and domain reputation, spam rates, and delivery errors, specifically for mail sent to Gmail recipients. Google's guidelines for senders explicitly state that they evaluate sending IP reputation based on volume consistency and recipient feedback. Similar tools exist for other major mailbox providers.
If you notice a sudden drop in deliverability, increased deferrals, or get placed on a blocklist (or blacklist), it's a clear sign that your current volume or sending practices are problematic. In such cases, you might need to reduce your volume temporarily, clean your lists, improve content, or revisit your IP warming strategy. Understanding what happens when your IP gets blocklisted is crucial for prompt recovery actions.
Views from the trenches
Best practices
Maintain highly engaged lists to justify higher sending volumes.
Segment your audience and send relevant content to improve engagement.
Implement robust list hygiene practices to minimize bounces and spam traps.
Use email authentication protocols (SPF, DKIM, DMARC) to build trust.
Common pitfalls
Sending large, inconsistent bursts of email from a single IP.
Ignoring spam complaints and high bounce rates.
Not monitoring IP reputation dashboards like Google Postmaster Tools.
Failing to warm up a new dedicated IP properly.
Expert tips
Recipient mailbox provider throughput is a major bottleneck for volume.
Performance metrics should guide your optimal sending volume.
Different email platforms may handle shared IPs and volumes differently.
Consider a buffer of extra IPs for unexpected volume spikes or issues.
Marketer view
Marketer from Email Geeks says that while increasing email volume certainly carries risks, reputation and sending speed are closely linked.
2024-01-19 - Email Geeks
Marketer view
Marketer from Email Geeks says there isn't a hard rule for optimal volume, and while larger volumes are possible, having less headroom can make management difficult when issues arise. It might be an ESP trying to simplify their operations rather than just selling more IPs.
2024-01-19 - Email Geeks
Finding your sweet spot
The optimal email volume per IP address isn't a single, fixed number. Instead, it's a dynamic balance influenced by your IP type (shared or dedicated), historical sending practices, engagement metrics, list quality, and the policies of recipient mailbox providers. For dedicated IPs, a general benchmark often cited is around 100,000 to 200,000 emails per month, or about 5,000 emails per day, to allow for proper reputation building. However, with excellent list quality and high engagement, I have seen IPs handle millions of emails per day successfully.
My recommendation is to focus on building a strong sending reputation through consistent volume, high engagement, and diligent list hygiene. Continuously monitor your deliverability and adjust your sending volume and strategy as needed. This proactive approach will ensure your emails land in the inbox, regardless of the precise volume you are sending.
Gmail and 
Outlook) scrutinize your sending IP's behavior. They track everything from spam complaints to open rates, bounce rates, and crucially, your sending volume and consistency. Sending too much too quickly, or having erratic sending patterns, can signal suspicious activity, leading to throttling, deferrals, or worse, placement on a blocklist (or blacklist, if you prefer that term).
Gmail recipients. Google's guidelines for senders explicitly state that they evaluate sending IP reputation based on volume consistency and recipient feedback. Similar tools exist for other major mailbox providers.
