What do the open rates 70%, 100%, and 0% mean for test accounts?
Michael Ko
Co-founder & CEO, Suped
Published 5 Jul 2025
Updated 19 Aug 2025
6 min read
When you're running email deliverability tests, the open rates you see, particularly those hitting 70%, 100%, or even 0%, carry specific meanings that differ significantly from typical marketing campaign metrics. These numbers are less about subscriber engagement and more about diagnostics, offering critical insights into your email infrastructure and how inbox providers perceive your sending practices. Understanding what these percentages indicate for test accounts is crucial for accurate troubleshooting and ensuring your emails reach their intended destination, the inbox.
My focus here is on interpreting these rates in a controlled testing environment, where you're typically sending to a small, known set of addresses, often referred to as seed lists. The insights gained from these specific open rates can help you preemptively identify and resolve issues before they impact your broader audience.
Understanding a 70% open rate
A 70% open rate in a test environment is often a very good sign. It indicates that your emails are successfully landing in the inbox for the majority of your test accounts, and the tracking pixel is firing correctly. For cold outreach and specific testing scenarios, a consistent 70% open rate is a strong indicator of good deliverability, suggesting that your setup is largely compliant with sender best practices and that your emails are not being heavily filtered.
While you might aim for 100% in tests, 70% is still excellent and suggests a robust setup. It implies that your sender reputation is solid and authentication protocols, such as DMARC, SPF, and DKIM, are correctly configured. This rate signals that inbox providers are trusting your emails, allowing them to reach the primary inbox for most of your seed list addresses. For example, some experts consider anything above 70% to be a good open rate for email spam tests. (Amplemarket.com).
If you are consistently seeing a 70% open rate in your test accounts, it’s a strong indicator that your foundational deliverability elements are in good shape. It means your emails are generally making it through the various filters and checks that inbox providers employ. To improve further, you might investigate the specific accounts that aren't opening to see if there are commonalities.
The meaning of a 100% open rate
A 100% open rate in a testing environment often reflects ideal conditions, indicating that every email sent to your test accounts was opened. This is typically what you aim for with a small, controlled seed list, as it means there are no immediate deliverability blocks or filtering issues preventing your emails from reaching the inbox and being tracked. It suggests that your email passed all authentication checks and was deemed trustworthy by the recipient's mail server.
However, it's also important to understand the nuances, especially with inbox providers like Gmail. Gmail caches images, which means opens are recorded even if the user doesn't explicitly load images. This can sometimes inflate open rates, making 100% appear more frequently than actual user engagement would suggest.
While a 100% open rate is generally positive for test accounts, it doesn't guarantee future success with large campaigns. It simply confirms that at the time of testing, your emails are not encountering immediate technical or reputation-based blocks. It's crucial to consider how email open rates are calculated to avoid misinterpretations.
Positive indicator
A 100% open rate on a test account typically signifies that your email passed all initial gateway filters and reached the primary inbox. It suggests strong domain and IP reputation with the inbox providers of your test accounts. This is the ideal scenario for a test.
What to confirm
Image loading: Confirm whether the opens are due to actual user engagement or automatic image caching by providers like Google.
Seed list variety: Ensure your test accounts cover a range of major inbox providers (Gmail, Microsoft, Yahoo) to get a comprehensive view.
Deciphering a 0% open rate
A 0% open rate on a test account is a critical red flag, signaling a significant deliverability problem. This usually means your emails are not reaching the inbox at all for those specific test accounts. They are likely being blocked, sent to the spam folder, or experiencing a technical failure before the open tracking pixel can load.
Several issues can cause a 0% open rate, ranging from serious reputation problems to misconfigurations. It's imperative to investigate immediately because if your test accounts aren't receiving emails, your actual recipients likely aren't either.
Common causes of 0% open rates
Blacklisting (or blocklisting): Your sending IP or domain may be listed on a public or private blacklist, preventing delivery. This is often the case if you see hard bounces or 5xx errors.
Spam folder placement: Emails are delivered, but to the spam or junk folder, where open tracking might be disabled or delayed. This often means your content or sender reputation is triggering filters.
Authentication failures: Missing or incorrect SPF, DKIM, or DMARC records can lead to emails being rejected outright. Always double-check your DNS settings.
Technical issues: Problems with your sending platform, mail server, or even network connectivity can prevent emails from being sent or delivered. This might require a comprehensive deliverability test to diagnose.
Factors influencing test open rates
Several underlying factors influence open rates in test accounts, and understanding them helps you interpret results more accurately. These factors often interact, making a holistic approach to deliverability testing essential.
For instance, your sender reputation plays a massive role. If your domain or IP has a poor reputation from previous sending, even test emails might be filtered. Similarly, the content of your email, including subject lines and body text, can trigger spam filters if it resembles known spam patterns, regardless of your intention. Even minor formatting issues or overly promotional language can cause problems in sensitive test environments.
Beyond content, technical setup is paramount. Correctly configured authentication records (SPF, DKIM, DMARC) are fundamental. Any misconfiguration can lead to emails being rejected, resulting in lower or zero open rates. Inbox providers also monitor your presence on blocklists, and a listing on even one significant blocklist can drastically impact your test results, pushing them towards 0%.
In test environments
I often see direct correlation between authentication success and opens. If SPF or DKIM fail, the open rate will likely be 0%. Reputation issues can cause immediate drops.
Control: You have full control over the test accounts, allowing for quick checks of spam folders or technical failures. This makes these specific open rates highly diagnostic.
Diagnostic focus: Low rates directly point to technical or reputation problems, like being on a blacklist or blocklist.
In live campaigns
Open rates are influenced by many factors beyond deliverability, such as subject line appeal, sending time, and audience engagement.
Variable factors: Open rates can fluctuate due to subscriber behavior, email client settings, and broader market trends. They offer a general benchmark of engagement.
Broader scope:Deliverability issues are harder to pinpoint due to the large scale and varied recipient environments.
Views from the trenches
Best practices
Always include a diverse set of email providers (Gmail, Outlook, Yahoo, etc.) in your seed list to cover different filtering behaviors.
Use clear, concise subject lines and engaging content in your test emails to mimic actual sending scenarios and avoid false positives.
Regularly check your domain and IP reputation using postmaster tools to preemptively identify potential issues affecting open rates.
Common pitfalls
Relying solely on open rates without cross-referencing other metrics like bounces, complaints, and click-through rates, can lead to incomplete analysis.
Testing with a too-small seed list might not provide a representative sample of how various inbox providers will handle your emails.
Ignoring soft bounces during tests, as they often indicate temporary issues that can escalate if not addressed promptly.
Expert tips
Implement a dedicated warm-up process for new IPs or domains to build a positive sending history with inbox providers.
Ensure all email authentication protocols (SPF, DKIM, DMARC) are correctly configured and aligned for optimal deliverability.
Segment your test lists by ISP to troubleshoot specific deliverability issues with particular providers more effectively.
Expert view
Expert from Email Geeks says a consistent 70% open rate in a testing environment means your foundational email setup is solid, but you should still analyze the non-opening accounts for specific issues.
2023-01-27 - Email Geeks
Marketer view
Marketer from Email Geeks says achieving a 100% open rate with seed lists is the goal, but it's essential to check if it's true inbox placement or just image caching by the ISP, especially for Gmail.
2023-03-10 - Email Geeks
Key takeaways for deliverability testing
Interpreting open rates of 70%, 100%, and 0% for test accounts is a vital part of proactive deliverability management. A high open rate signals strong deliverability, while a zero percent rate demands immediate attention. By understanding the specific implications of each percentage and the underlying factors influencing them, you can pinpoint issues before they affect your live campaigns. Regular and informed testing is your best defense against deliverability challenges, ensuring your messages consistently reach your audience.
Deliverability issues are harder to pinpoint due to the large scale and varied recipient environments.
