What are recommended email send volume increases to avoid reputation damage and how to recover from hits?
Michael Ko
Co-founder & CEO, Suped
Published 3 Aug 2025
Updated 19 Aug 2025
9 min read
Email deliverability is a complex dance between your sending practices and the receiving mail servers (ISPs). One of the most common pitfalls I see businesses fall into is an erratic email sending volume. You might be accustomed to sending a certain number of emails daily, but then a special campaign comes along, and you decide to send a massive burst. This sudden spike can instantly damage your sender reputation, leading to lower inbox placement or even a spot on a blocklist (or blacklist).
Internet Service Providers (ISPs) like Gmail and Outlook closely monitor sending patterns. Consistency is key. A sudden increase in volume, especially from a domain or IP address that hasn't sent much email before, looks suspicious. It can mimic spamming behavior, triggering automated filters that then direct your emails to the spam folder or reject them entirely. This is why understanding how to gradually scale your email volume, and what to do if your reputation takes a hit, is crucial for any sender.
In this guide, I will share the recommended strategies for increasing your email send volume without jeopardizing your reputation and provide actionable steps to recover if things go wrong. We will also look at insights from real-world deliverability experts.
The impact of sudden volume increases
Email reputation is like a credit score for your sending domain and IP address. ISPs use it to determine whether your emails are trustworthy and should land in the inbox. Many factors contribute to this score, including spam complaints, bounce rates, spam trap hits, and, critically, sending volume and consistency. Sudden, large increases in email volume without a prior sending history can be a major red flag for these providers.
ISPs expect senders to build their reputation gradually, much like a new business builds credit. This process is often called IP or domain warming. It involves starting with small volumes of highly engaged recipients and slowly increasing the volume over time. This allows ISPs to observe positive sending behavior, such as low complaint rates and high engagement, building trust in your sending practices.
When you deviate from your typical sending patterns, especially with a significant upward surge, it can trigger automated spam filters. These filters are designed to protect recipients from unsolicited mail and phishing attempts. A sudden jump in volume, without a corresponding history of high engagement and low complaints at that volume, can easily lead to your emails being flagged as suspicious, even if your content is legitimate. This is a crucial aspect of how email sending practices impact reputation.
Recommended volume increases for healthy scaling
For new senders or those introducing new IP addresses or domains, the recommendation is to start with very low volumes. Some experts suggest beginning with as few as 50-100 emails daily, gradually increasing over 4-6 weeks. The goal is to allow ISPs to observe consistent, positive sending behavior before you scale up significantly. This measured approach helps to establish a strong initial email sending volume.
For established senders planning a larger, one-off campaign, the key is to avoid drastic spikes. A good rule of thumb I've seen widely discussed is to limit your daily, weekly, and monthly send volume increases to between 20-50% of your average. Exceeding this range can signal abnormal behavior to ISPs, potentially triggering filters and damaging your reputation. Remember that volume fluctuations affect deliverability.
The exact safe percentage also depends on your baseline volume. A 50% increase from 100,000 emails to 150,000 might be less impactful than a 50% increase from 2 million to 3 million emails, as the latter might trigger filters due to the sheer magnitude of the increase. It is about the perceived shock to the system. Always prioritize consistent, gradual growth over sudden bursts to maintain a positive sender reputation. For more details, explore email frequency and volume management.
Period
Recommended Max Increase
Daily
20-50% of average daily volume
Weekly
20-50% of average weekly volume
Monthly
20-50% of average monthly volume
How to recover from reputation damage
If your domain or IP reputation has suffered due to sudden volume spikes or other issues, recovery is possible but requires a strategic approach. The first step is often to pause or significantly reduce email sending. This cooling-off period, which can range from a few days to a month, allows ISPs to see that the problematic sending has ceased. During this time, you should focus on identifying and rectifying the root cause of the reputation damage. Our guide on recovering email domain and IP reputation provides further insights.
After the cooling-off period, restart sending at very low volumes, targeting your most engaged recipients. This initial low-volume sending to engaged users helps rebuild trust and demonstrates to ISPs that you are now sending desirable content. Gradually increase the volume over time, adhering to the 20-50% daily increase guideline. This careful re-warming process is crucial. You can also monitor your domain reputation through Google Postmaster Tools and other similar services.
Beyond volume adjustments, a thorough audit of your email program is essential. This includes checking your authentication records (SPF, DKIM, DMARC), ensuring your email list is clean and free of invalid or unengaged addresses, and reviewing your content for any spam triggers. Proactive monitoring and adherence to best practices are the best ways to avoid future reputation issues. Understanding why your emails go to spam can help prevent future incidents.
Beyond volume: Other critical reputation factors
Immediate actions
Pause sending: Halt all problematic email campaigns immediately to stop further damage.
Identify cause: Determine what triggered the reputation hit (e.g., sudden volume, high bounces, spam complaints).
Segment list: Prepare to send only to your most engaged subscribers first.
While sending volume is a critical factor, it is by no means the only one. A holistic approach to email deliverability includes several other key elements that can make or break your inbox placement, regardless of your sending volume. Ensuring these factors are optimized will significantly bolster your sender reputation and resilience against reputation damage.
Email authentication: Properly configure SPF, DKIM, and DMARC records. These provide crucial validation to ISPs that your emails are legitimate and from an authorized sender. Without these, your emails are more likely to be flagged as spam.
List hygiene: Regularly clean your email lists to remove inactive, invalid, or bouncing addresses. Sending to a dirty list increases your bounce rates and the risk of hitting spam traps, which can severely damage your reputation. Understand what spam traps are and how to avoid them.
Engagement metrics: High open rates, click-through rates, and low unsubscribe rates signal to ISPs that your recipients value your emails. Conversely, low engagement, high spam complaints, or high bounce rates indicate poor list quality or irrelevant content, negatively impacting your reputation.
Content quality: Avoid spammy language, excessive exclamation points, and suspicious links. Focus on providing value to your audience to encourage positive engagement.
By proactively managing these aspects alongside your sending volume, you build a robust sender reputation that is more resilient to minor fluctuations. Remember, delivering emails is not just about sending them, it is about getting them to the inbox where they can be seen. For a deeper understanding of your sending health, consider regularly checking your email domain reputation.
Views from the trenches
Best practices
Maintain consistent daily, weekly, and monthly email sending volumes.
Gradually increase send volumes by 20-50% to avoid sudden spikes.
Prioritize sending to highly engaged subscribers during reputation rebuilding phases.
Regularly monitor your domain and IP reputation using available tools.
Common pitfalls
Sending large, unscheduled email blasts without prior warming up.
Ignoring low engagement rates and continued sending to inactive users.
Failing to clean email lists, leading to high bounce rates and spam trap hits.
Neglecting email authentication, which makes your emails look suspicious.
Expert tips
Even if you're sending at high volumes, a 20-50% increase can be problematic if the total volume is extremely large.
If your reputation is hit, pull back sending to only those who have engaged within the last 30 days.
Consistent engagement is key; focus on sending emails that recipients genuinely want to receive.
Understand that the 'shock' element of a volume increase is what filters react to the most.
Marketer view
Marketer from Email Geeks says that recommendations for email volume increases typically fall between 20-50%.
July 30, 2019 - Email Geeks
Marketer view
Marketer from Email Geeks says that the 20-50% increase guideline applies to daily, weekly, and monthly changes across all domains.
July 30, 2019 - Email Geeks
Building and maintaining trust
Managing email send volume is a critical component of maintaining a healthy sender reputation and ensuring strong deliverability. Abrupt increases can quickly lead to reputation damage, resulting in your emails landing in spam folders or being rejected outright. By adopting a gradual approach to volume increases (often referred to as warming up), you can build trust with ISPs and improve your chances of consistently reaching the inbox. Remember, consistency and positive engagement are the pillars of a good sender reputation.
Should your reputation take a hit, pausing problematic sends, re-engaging with your most active audience at lower volumes, and diligently cleaning your email lists are essential steps. Combine these efforts with robust email authentication to rebuild trust and get your email program back on track. Proactive monitoring and adherence to best practices are always your best defense against deliverability issues. For more detailed insights, you can review our content on the latest email deliverability issues.
Gmail and 
Outlook closely monitor sending patterns. Consistency is key. A sudden increase in volume, especially from a domain or IP address that hasn't sent much email before, looks suspicious. It can mimic spamming behavior, triggering automated filters that then direct your emails to the spam folder or reject them entirely. This is why understanding how to gradually scale your email volume, and what to do if your reputation takes a hit, is crucial for any sender.
