How should I define unengaged subscribers for removal from my email list?
Matthew Whittaker
Co-founder & CTO, Suped
Published 19 May 2025
Updated 15 Aug 2025
6 min read
Defining an unengaged subscriber is critical for effective email marketing and maintaining a strong sender reputation. It is not just about removing contacts, but about intelligently refining your audience to ensure your messages reach those who want them. A high number of unengaged recipients can significantly harm your email deliverability.
Failing to address unengaged subscribers can lead to lower open and click rates, increased spam complaints, and potentially land your domain or IP on a blocklist (or blacklist). These negative signals tell Internet Service Providers (ISPs) that your emails are not valuable, impacting inbox placement for all your subscribers.
Understanding engagement and its impact
An unengaged subscriber is typically someone who has consistently failed to interact with your email campaigns over a specified period. This lack of interaction signals to ISPs like Gmail and Outlook.com that your emails might be irrelevant or unwanted, even if recipients haven't explicitly marked them as spam.
The presence of a large segment of unengaged contacts negatively skews your engagement metrics, making your overall list appear less healthy. This can lead to your emails being directed to the spam folder, or even worse, cause your sending IP or domain to be added to various email blacklists or blocklists. Such a scenario can be difficult to recover from, affecting all your future email campaigns.
ISPs heavily rely on engagement data to determine a sender's reputation. If a significant portion of your emails are going unread or unclicked, it suggests that your content isn't resonating with your audience. This perception can lead to broader deliverability issues, hindering your ability to reach even your most active subscribers.
Key metrics to define unengagement
Traditionally, email opens and clicks have been the primary metrics for gauging engagement. While clicks remain a strong indicator, open rates have become less reliable due to privacy features like Apple Mail Privacy Protection, which pre-fetches emails. This means you might see an open even if the recipient never actually viewed the email.
Therefore, it is crucial to consider a broader range of metrics when defining unengagement. Beyond email specific actions, look at website activity, purchase history, customer support interactions, and even mobile app usage. These holistic engagement signals provide a more accurate picture of a subscriber's interest in your brand, not just your emails.
To truly define unengaged subscribers, you should establish a clear set of criteria based on multiple data points. This allows for a more nuanced approach than simply relying on a single metric, ensuring you do not prematurely remove potentially valuable contacts who engage with your brand through other channels.
Metric
Description
Reliability
Email opens
Subscriber views the email content.
Decreasing due to privacy features
Email clicks
Subscriber clicks a link within the email.
High, indicates active interest
Website visits
Subscriber visits your site after receiving an email.
High, strong intent signal
Purchase history
Subscriber makes a purchase.
Very high, direct business value
Login activity
Subscriber logs into an account.
High, for service-based businesses
Form submissions
Subscriber completes a form on your site.
High, indicates interaction
Setting timeframes and thresholds
There is no universal "magic number" for how long a subscriber must be inactive before being considered unengaged. The appropriate timeframe largely depends on your sending frequency, industry, sales cycle, and the nature of your content. For a daily newsletter, three months of inactivity might be significant, whereas for a quarterly update, nine months might be acceptable.
Many marketers consider a subscriber unengaged after 6 to 18 months of no interaction across any channel, depending on their specific email program. Before outright removal, it is always advisable to attempt a re-engagement campaign. This provides a final opportunity for inactive subscribers to reaffirm their interest and can help you identify those who still want to hear from you.
Implementing a "sunset policy" is a structured way to manage unengaged subscribers. This policy defines a clear timeline and process for identifying, attempting to re-engage, and eventually removing subscribers who remain inactive. This proactive approach ensures your list stays healthy and reduces the risk of deliverability issues. To learn more about this, consider our guide on best practices for sunsetting inactive email subscribers.
Flexibility is key
Your definition of unengaged should not be static. Regularly review your engagement metrics and adjust your timeframes based on performance, changes in your email program, or evolving ISP requirements. What works today might need fine-tuning six months from now.
Strategic considerations for removal
Removing unengaged subscribers might seem counterintuitive if you are focused on list growth, but it is a critical step for improving your email deliverability and overall return on investment. Continuing to mail uninterested recipients not only wastes resources but also signals poor sender reputation to ISPs, increasing your chances of landing on a blacklist.
While the ultimate goal is often removal (or suppression), the journey there usually involves re-engagement attempts. A thoughtful re-engagement strategy can revive a portion of your inactive audience. We have a detailed resource on how to re-engage inactive email subscribers. If re-engagement fails, suppression is the next logical step.
When it comes to managing these subscribers, you typically have two main options: suppression or deletion. Suppression means the contact remains in your database but is excluded from future mailings, allowing you to retain their data for other purposes. Deletion, on the other hand, permanently removes them from your system. The choice depends on your data retention policies and marketing strategy.
Suppression
Data retention: Subscriber data remains in your system.
Future use: Useful for retaining historical data or for other marketing channels.
Email exclusion: Prevents emails from being sent to them.
Compliance: Helps with opt-out management.
Deletion
Data removal: Permanently removes subscriber data.
List hygiene: Cleans your list entirely, reducing costs.
GDPR/CCPA: May be required for data privacy compliance.
Final step: Often follows a failed re-engagement or sunset policy.
Views from the trenches
Best practices
Analyze your specific customer data to understand their interaction patterns over time.
Implement a re-engagement campaign before removing subscribers to give them a last chance to respond.
Consider non-email metrics like website logins or purchase history for a holistic view of engagement.
Regularly review and adjust your unengagement criteria based on evolving email program performance.
Common pitfalls
Relying solely on open rates as a measure of engagement can be misleading due to privacy features.
Using a generic, industry-wide timeframe for inactivity without considering your specific business cycle.
Failing to implement a structured sunset policy, leading to a build-up of inactive contacts.
Hesitating to remove unengaged subscribers, which can negatively impact overall deliverability and sender reputation.
Expert tips
The optimal timeframe for considering a subscriber unengaged varies greatly by your audience and sending frequency.
Inactive subscribers, if left on the list for too long, can severely degrade your email deliverability metrics.
Your sales cycle and product delivery methods should significantly influence your definition of engagement.
The goal is to prevent a large accumulation of unengaged contacts from hurting your email delivery.
Marketer view
Marketer from Email Geeks says: My current organization considers subscribers unengaged after one year, but we only send fundraising emails to those active within six months.
2020-03-27 - Email Geeks
Marketer view
Marketer from Email Geeks says: The timeframe for defining unengaged subscribers typically ranges from 6 to 18 months, depending on the target group and email frequency.
2020-03-27 - Email Geeks
Cultivating a healthy email list
Effectively defining unengaged subscribers is a cornerstone of maintaining a healthy and high-performing email list. It moves beyond a simple time-based metric to a strategic assessment of subscriber value based on comprehensive engagement data.
By proactively identifying and managing these contacts, you not only improve your sender reputation and email deliverability but also ensure your marketing efforts are focused on an audience genuinely interested in your message, ultimately leading to better campaign performance and a higher return on investment.
Gmail and 
Outlook.com that your emails might be irrelevant or unwanted, even if recipients haven't explicitly marked them as spam.
