Summary
An acceptable email bounce rate is crucial for maintaining a healthy sender reputation and ensuring strong email deliverability. While a zero bounce rate is ideal but often unachievable, industry benchmarks generally suggest keeping your total bounce rate below 2%. Both the percentage and the absolute volume of bounces play a role, signaling to mailbox providers (MBPs) the quality of your email list and your adherence to best practices. High bounce rates, especially hard bounces, indicate issues with list acquisition or hygiene and can lead to throttling, blocklisting, or even complete blocking of your emails by ISPs.
Key findings
- Benchmark: A healthy email bounce rate is generally considered to be below 2%.
- Impact on reputation: Consistently high bounce rates severely harm sender reputation, leading to throttling or blocking by ISPs.
- Hard vs. soft bounces: Hard bounces (permanent failures) are more damaging and should be suppressed immediately, while soft bounces (temporary failures) require careful management.
- List quality indicator: High bounce rates suggest poor list acquisition practices or a lack of regular list cleaning.
- ISP perspective: MBPs use both the bounce rate percentage and the absolute number of bounces as signals of sender quality.
Key considerations
- Proactive list hygiene: Regularly clean your email lists to remove invalid or inactive addresses before sending.
- Monitor hard bounces: Implement immediate suppression for hard bounces to prevent recurring issues, as discussed in our guide on how hard bounces impact deliverability.
- Soft bounce strategy: Develop a clear strategy for handling soft bounces, including retry attempts and eventual suppression for persistent failures.
- Source of acquisition: Investigate the source of new email addresses if you observe a sudden increase in bounces to identify and rectify problematic acquisition methods. EmailLabs emphasizes this in their discussion on understanding email sender reputation.
- ESP definitions: Be aware that different Email Service Providers (ESPs) may define hard and soft bounces uniquely.
What email marketers say
Email marketers widely agree that bounce rates are a critical metric for deliverability, significantly influencing sender reputation. While zero bounces are an ideal, unattainable goal, maintaining a low percentage, typically under 2%, is a common benchmark. Marketers stress the importance of differentiating between hard and soft bounces and taking appropriate action, like immediate suppression for hard bounces. They also highlight the need to review data collection practices to prevent bounces at the source, acknowledging that a low bounce rate is just one piece of the deliverability puzzle. The industry consensus leans towards focusing on the rate rather than just the volume, especially for larger senders, as it points to underlying list quality and compliance issues.
Key opinions
- Percentage over volume: For compliance and overall list health, the bounce rate percentage is often more indicative of issues than the absolute volume.
- 2% threshold: Many marketers aim to keep their total bounce rate below 2% as a sign of good data collection practices.
- Hard bounce suppression: It is strongly recommended to suppress hard bounces after the first occurrence, regardless of the ESP's default handling.
- Data acquisition review: A noticeable hard bounce rate should prompt a review of the acquisition source to prevent future deliverability problems. Further information on this is available in our article on how email sending practices impact domain reputation.
- Bounce types: Marketers generally differentiate between hard and soft bounces and manage them differently based on their nature.
Key considerations
- Holistic view: A low bounce rate alone does not guarantee deliverability success, as other factors like subscriber engagement and proper opt-in processes are also crucial.
- ESPs definitions: Be aware that each ESP might have its own definitions for hard, soft, and block bounces, requiring careful understanding during migrations.
- Soft bounce evaluation: Even for soft bounces, marketers should analyze SMTP reasons and consider whether repeated attempts to full inboxes are worthwhile. The CampaignHQ Blog also offers insights on why bounce rates matter.
- Volume vs. rate context: While rate is often primary, for very small lists, the absolute volume of bounces might still be significant and require attention.
Marketer view
A marketer from Email Geeks indicates that for compliance checks, the bounce rate percentage is more relevant than volume, as a 5% bounce rate is equally problematic for a list of 1,000 or 1,000,000 contacts.
Marketer view
A marketer from Email Geeks observes that a total bounce rate under 2% generally suggests good data collection practices, though it is only one indicator of deliverability success.
What the experts say
Email deliverability experts highlight that sending to non-existent addresses is a critical red flag for ISPs, indicating poor list quality or inadequate permission practices. They emphasize that while some mailbox providers (MBPs) consider bounce rates as ratios and others as volumes, the underlying issue of targeting invalid addresses will always negatively impact sender throughput and reputation, potentially leading to blocklisting. Experts also note that the precise definition of hard and soft bounces can vary significantly across different ESPs and MBPs, which adds complexity to bounce handling. They advocate for maintaining very low bounce rates for subsequent sends and view robust bounce handling as essential, though often an underdeveloped aspect of email infrastructure due to what they describe as industry-wide tech debt.
Key opinions
- Permission signal: Sending to non-existent addresses signals a failure in obtaining adequate permission and poor list hygiene.
- Reputation impact: High bounce rates, regardless of being a ratio or volume, will negatively impact IP and domain reputation, leading to blocks or spam folder placement.
- Target rates: For initial sends, delivery failures for non-existent addresses should be below 4%, and below 1% for subsequent sends.
- ISP variations: The way bounces affect reputation can vary by recipient domain; for example, Yahoo's full message visibility allows for more detailed mapping than Google's.
- Industry challenge: Bounce handling is identified as an industry-wide technical debt, with no single entity performing it perfectly.
Key considerations
- Continuous list hygiene: Maintain rigorous list cleaning to remove non-existent addresses promptly, preventing issues that affect your sender reputation.
- Data transparency: The lack of consistent bounce definitions across ESPs and MBPs highlights a need for greater data transparency in the industry.
- IP vs. domain impact: Understand that non-existent user metrics can affect IP address, EHLO value, and SPF domain for some systems (like Google), while others (like Yahoo) can link them to URLs within the message.
- Preventive measures: Focus on preventing bounces by optimizing address collection processes rather than solely reacting to them. Mailgun provides helpful advice on what to do about email bounces.
Expert view
An expert from Email Geeks explains that sending to non-existent addresses signifies insufficient permission gathering and inadequate list hygiene, indicating a focus on volume over recipient regard.
Expert view
An expert from Email Geeks recalls that AOL previously blocked or spam-foldered mail from IPs exceeding a 10% bounce rate to non-existent users.
What the documentation says
Official documentation and research consistently highlight the critical role of bounce rates in determining email deliverability and sender reputation. A general consensus points to a bounce rate below 2% as acceptable, with the ideal being as close to 0% as possible. High bounce rates, particularly hard bounces, are clear indicators to ISPs of a poor-quality list or spammy sending practices, leading to negative consequences like throttling, blocklisting, and decreased inbox placement. Documentation also underscores that even if other engagement metrics are strong, an uncontrolled bounce rate can severely undermine a sender's overall reputation and deliverability. The emphasis is on proactive list maintenance and understanding how different bounce types are interpreted by various mailbox providers.
Key findings
- Acceptable range: A bounce rate of less than 2% is widely considered acceptable, with the ideal being near 0%.
- Reputation destroyer: A high bounce rate can destroy sender reputation, regardless of good open or click-through rates.
- ISP action: Consistently high bounce rates trigger ISPs to throttle or block email delivery.
- List engagement factor: The optimal bounce rate can vary based on email list engagement and the nature of sending.
- Blocklist risk: Keeping hard bounces low is crucial to avoid being placed on email blocklists.
Key considerations
- Proactive management: Do not ignore bounces. They are direct feedback that requires action to maintain deliverability and avoid being flagged as a spammer.
- Hard bounce priority: Focus on minimizing hard bounces, as they signal permanent issues and are most damaging to reputation. Our article what is an acceptable email bounce rate provides more detail.
- Engagement signals: Low recipient engagement (brief opens, no interaction) can contribute to higher bounce rates and negatively impact sender reputation. Learn more about improving sender reputation for better deliverability.
- Regular monitoring: Continuously monitor bounce rates to quickly identify and address issues, ensuring your messages reach the inbox effectively.
Technical article
Documentation from EmailLabs indicates that sustained high bounce rates can result in ISPs throttling or blocking email delivery from a sender's domain, severely impacting their reputation.
Technical article
Documentation from Mailgun advises that minimizing bounce rates, particularly hard bounces, is critical for a robust email reputation, ensuring messages reach the inbox and avoiding blocklists.
Related resources
10 resources
Related pages
What is an acceptable email bounce rate, and how do hard and soft bounces differ?
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How are email bounce rates calculated and what is considered a good bounce rate?
What is a reasonable soft bounce tolerance in email marketing?
How do bounces and phishing attacks affect email deliverability and domain reputation?
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