Calculating Email Bounce Rate
As mentioned above, the bounce rate is a percentage calculated by dividing the number of bounced emails by the total number of emails sent (both delivered and bounced), then multiplying the result by 100 to express it as a percentage.
Summed up, the formula should look like this:
Let’s assume that you have sent 1000 emails in your last mailing campaign. Your ESP reported that 20 bounced, so you calculate 20/1000. Afterward, you have to multiply it by 100 to get the percentage.
The formula will look like this: (20/100) x 100. This gives you a bounce rate of 2%. Since 5% or below rates signal good email deliverability, you can pat yourself on the back, for it indicates healthy email list hygiene and effective delivery practices.
On the other hand, you can also calculate your bounce rate using a code snippet. For example:
Causes of High Email Bounce Rates
There are different factors leading to email bounces, including various technical issues, list quality, and lack of authentication. Some of them may cause increased bounce rates, and, in time, affect your mailing effectiveness. The good news? Their negative impact can be avoided if addressed in time. Therefore, let’s take a look at them:
- Internet Service Providers (ISP) blocking emails due to spam analysis. Even if you are not engaging in it, your emails can be flagged as spam if you:
- Use spammy words.
- Include content that resembles known spam (never ask your relatives for money using email!).
- Send large amounts of emails in a short period.
To avoid this, it is advisable to run your email content through spam filter testing tools before sending them. This way, any content that could trigger spam filters will be properly identified.
- Blacklisted IPs. Is your email bounce rate higher than usual? Then you should probably monitor your IP reputation to make sure it hasn’t been blacklisted. For that, you can use tools like SenderScore or Blacklist Check. If your IP address is blacklisted, you can contact the responsible DNSBL (Domain Name System-based Blackhole List). After addressing the issues that led to the blacklisting, you can request removal from the list.
- List quality. Using outdated email addresses, or purchased email lists, usually leads to a great number of non-existent or invalid contacts, causing high bounce rates. To avoid this, scrub your email contact lists regularly, removing invalid, inactive, or incorrect email addresses. You can also use tools like Abstract API to validate mailing addresses before sending your emails.
- Lack of email authentication. Protocols like DMARC, SPF, and DKIM help guarantee that an email is genuinely from the sender it claims to be. Not using them can make your IP address look suspicious to ESP, increasing your emails’ chances of ending in a spam folder or bouncing. Using dedicated sender domains and consistently reviewing your authentication records helps ensure your emails are properly authenticated.
Email Bounce Rate Benchmarks
Different industries may have varying average bounce rates due to the nature of their email lists and how frequently they clean and update them. While a bounce rate of 2-3% is common in the media and publishing industry, the retail and e-commerce industry normally aims for a 1-1.5% bounce rate.
Broadly speaking, the average bounce rate for most industries tends to be between 0% and 3%. The threshold indicating possible (but not ascertained) issues with email list quality, technical errors, or compliance problems is, typically, a bounce rate of 2 %. When it reaches 5% bounce rates are considered high and might require intervention.
Email service providers (ESPs) like GetResponse, Constant Contact, and Mailchimp often analyze their clients' statistics to establish average benchmarks for email bounce rates. These benchmarks can be categorized based on regional or country-specific criteria and, especially, by doing cross-industry research:
Sources: https://www.getresponse.com/resources/reports/email-marketing-benchmarks
https://mailchimp.com/es/resources/email-marketing-benchmarks/
It's helpful to compare your bounce rate with industry-specific benchmarks and regulations to gauge your performance accurately. Just, take into account that bounce rates may vary greatly from email provider to email provider. Among other things, this is mostly due to each ESP’s users and their audiences, as well as due to the ESP’s classification of what counts as a bounce, and its users’ knowledge of best mailing practices. Nonetheless, they provide actionable insights for optimizing email campaigns, to comply with these industry-specific benchmarks.
As you can see, several industries do not comply with the 2% bounce rate threshold. This does not mean that they are failing, overall, in their mailing campaigns (a +5% bounce rate indicates it)―just that there’s room for improvement. And this, with the right tools, is easy to achieve.
Email Deliverability and Bounce Rate
Email bounce rate and email deliverability are inversely related. A high bounce rate negatively impacts deliverability, by signaling poor email list quality or technical issues to email service providers (ESPs).
This weakens your sender’s reputation, a critical factor in determining whether emails are delivered to the inbox. In turn, a low sender reputation reduces the overall deliverability of your emails (how likely is that they reach the recipient’s inbox ―not being bounced, and passing spam filters). Over time, this can result in even higher bounce rates or, in severe cases, the suspension of your email account or domain.
When analyzing your bounce rate to understand its impact on Email Deliverability, it is essential to differentiate between soft bounces and hard bounces.
Hard bounces are often irrecoverable since they are caused by permanent failures, like invalid or non-existent email addresses. The only course of action to improve deliverability would be to delete those addresses.
Conversely, soft bounces are caused by temporary issues, such as a full mailbox, spam filter blocks, or server downtime. This means that they can be solved by waiting for the recipient's mailbox to become available or addressing the underlying issue, such as adjusting email content or improving sender authentication.
Non-delivery reports (NDR) often provide further insights into email bounce’s causes. They are also called Delivery Status Notifications (DSNs) or “bounce messages”.
Often, such messages include 5XX codes for permanent failures (like unexisting addresses) and 4XX codes for temporary ones, as well as a short description of what originates the failure in deliverance. Some NDRs may even provide feedback, with suggestions for improving your metrics.
You can use NDRs to distinguish between list hygiene issues that are solved by scrubbing your contact lists, and technical problems. That way, you will know straightforwardly what went wrong and how to address the issue at hand, as soon as possible.
According to several studies, removing invalid or inactive addresses from your contact list can improve your bounce rate by up to 15%. Delivery and, consequently, opening rates also increased by 25% while conversion rates doubled.
Implementing other best practices for mailing, such as monitoring your ESP reputation, verifying email addresses, and adjusting your email content to ensure compliance with spam filters also helps to improve bounce and delivery rates.
Email List Management
Maintaining a clean, up-to-date email list is one of the most effective strategies to reduce email bounce rates while increasing deliverability and recipient engagement. It also ensures compliance with anti-spam laws, fostering trust with subscribers.
Removing inactive subscribers regularly and validating email addresses are key practices for good list hygiene. Additionally, these actions offer several key benefits for email campaigns and deliverability.
First of all, they significantly lower the risk of your emails reaching spam traps, which can lead to blacklisting by email service providers (ESPs), and prevent emails from being sent to invalid addresses, reducing bounce rates.
Secondly, maintaining a clean list ensures that your engagement metrics, such as open and click rates, remain accurate and reliable. This will allow you to optimize your campaign performance using trustworthy data.
Another benefit of email list hygiene is reduced costs when using ESPs that charge based on the size of your email list. By ensuring that your list contains only active and valid contacts, you avoid paying for inactive or invalid addresses, ensuring your investment is efficiently spent. Furthermore, focusing your campaigns on an active audience improves engagement metrics, such as open and click rates.
For its part, monitoring soft bounces allows you to assess whether specific email addresses can be recovered before they escalate into hard bounces (which are lost causes). This approach improves deliverability metrics, as well as saves potentially valid contacts.
Another strategy to maintain a clean email list is to provide your contacts t with a clear and easy option to unsubscribe from the start. Double opt-in methods are a key part of this approach.
These methods involve requiring subscribers to confirm their email address after signing up, typically using a confirmation link. By doing so, double opt-in strategies help you reduce the risk of spam complaints or invalid addresses, whether fake or mistyped.
Other basics of permission-based email marketing include:
- Visible unsubscribe buttons, in every email you send.
- Avoid buying email contact lists, which reduces the likelihood of hard bounces and spam.
- Clearly specifying your email frequency from the beginning
These practices will ensure that only genuinely interested users are added to your list, improving its quality and enhancing your sender reputation. All of which will positively impact your email deliverability and metrics.
Strategies to Reduce Email Bounce Rate
Further mailing best practices to reduce email bounce rate encompass email verification and list cleaning, as well as contact segmentation and optimizing email content. Let’s see how each of them can help you improve your email campaigns.
Email List Verification and Cleaning
Email List management can be viewed as an ongoing process, aimed at maintaining the quality and engagement of your emails’ recipients. In contrast, verifying email addresses before issuing promotional or informational messages and cleansing your contact list afterward are periodic activities. It is advisable to perform them regularly to ensure list accuracy, improve deliverability, and maintain acceptable bounce rates.
To review your email list you can use tools such as NeverBounce, Abstract API, or ZeroBounce, which specialize in email validation. When choosing one, make sure it offers real-time verification during the sign-up process to prevent invalid emails from entering your list.
You can also choose an ESP that offers built-in email verification tools or integrations as part of its functionality. This approach can make it easier to maintain list hygiene directly within their platform.
Optimizing Email Content
Another highly recommended practice to diminish email bounce rate is tailoring your email content to ensure it isn’t mistaken by ESPs for spam or malicious messages. To achieve this, some actions you can consider are:
- Avoiding spammy language. Using words commonly associated with spam content can cause your emails to be flagged as spam and, as a result, lead to bounces. Phrases you might want to avoid include 'best prices,' 'special promotion,' 'get it now,' 'exclusive deal,' 'winning,' 'no-cost,' 'for free,' and 'urgent,' among similar terms. In other words, steer away from excessive use of sales-oriented language. Spam word checkers can help you prevent accidental usage of such terms.
- Create a clean HTML code. Emails may include HTML codes to feature visual elements that increase audience engagement. Nonetheless, poorly coded or excessively complex HTML tends to trigger ESPs’ spam filters, leading to bounces. To create clean HTML it is better to:
- Use a table-based layout for better compatibility across email clients.
- Prioritize single-column layouts, for better mobile responsiveness.
- Make sure CSS or <style> tags are internal, to ensure consistent rendering.
- Minimize code bloat and avoid unsupported elements, such as JavaScript, forms, and complex animations.
- Personalize content. Including personalized elements not only enhances the recipient engagement but also functions as an authenticity signal, helping your email bypass spam filters. Refraining from including excessive links or large attachments is essential to prevent your messages from looking suspicious.
Segmentation of Contact Lists
Segmenting your subscribers’ list based on user behavior and engagement will help you develop targeted campaigns, which can significantly improve your email bounce rate. For example, leveraging behavioral data allows you to design re-engagement campaigns tailored to meet specific user interests or create email content that resonates more effectively with your audience.
To effectively segment your contact list, follow the steps below:
- Define behavioral metrics, that is the behaviors you want to use for segmentation. Open rates, clicks, purchase frequency, and website interactions are commonly used for this. Take into account that:
- You can use ESPs like Mailchimp or GetResponse to track engagement metrics.
- Lifecycle insights are provided by CRMs such as HubSpot or Salesforce.
- Google Analytics and similar tools help to segment based on on-site behavior.
- Using the collected data, specify clear audience segments. Useful categories include highly engaged users, inactive users, loyal customers, and prospective buyers. Some ESPs allow for automated segmentation.
- Tailor campaigns for each segment, addressing its particular needs and interests. Optimize these campaigns by conducting A/B tests to refine messaging and design.
- After analyzing campaign performance, reorganize your list’s segments to ensure they remain relevant and up-to-date. Bounce addresses, unsubscribes, and spam complaints should be organized into suppression lists, to avoid re-sending to problematic recipients.
Tools for Managing Bounce Rate
Technological advances changed the picture in more than one way. Modern spam filters and advanced security protocols have turned email communication into a challenge akin to scaling Everest—daunting, but entirely conquerable with the right tools in hand.
As you have probably noticed, several mailing functions can be crucially eased by email platforms and tools, reducing bounce rate likeability. More specifically:
- Email validation. Tools such as Abstract API, ZeroBounce, and UseBouncer help you ensure every recipient on your mailing list is legitimate, reducing the risk of sending emails to invalid or inactive addresses.
- Tracking and testing emails. CRM software and tools, like Mailchimp and Mailtrap Email testing, can be used to obtain insights into potential bounce risks (for example, spam triggers) and to track recipient interactions.
- Bounce notifications. Some tools generate automated bounce notifications, making it easier to keep track of email deliverability. Some ESPs that offer this functionality include GetResponse and Constant Contact.
- Real-time list management. Organizing your contact list can be a time-consuming task. Luckily, platforms like HubSpot, Moosend, and various other ESPs offer automated solutions that simplify this, ensuring accuracy and efficiency.
Types of Email Bounces
As we mentioned above, there are two types of email bounces: soft bounces and hard bounces. The key difference lies in whether these bounces can be reversed, which ultimately hinges on their underlying causes.
Soft bounces are often caused by temporary issues, like full inboxes, server problems, and excessively large or spammy emails. Hard bounces, on the other hand, result from permanent issues, such as blocked and invalid email addresses, or non-existent domains.
While, usually, soft-bounced addresses receive the sent email after a couple of resends, hard-bounced addresses need to be removed immediately from contact lists. Otherwise, this may lower your credibility with Internet Service Providers, affecting your overall deliverability.
Sometimes, when resending the email doesn’t resolve soft bounces, but the cause is identified, specific solutions can be applied. For example:
- Server issues on the recipient’s email server. If bounces continue after resending the email, you can contact the recipient through alternative communication means to update their email address.
- Full recipient mailbox. If the issue persists, consider removing the subscriber after multiple attempts.
- Too large email size. Optimize email content and images to reduce overall size. Test emails before sending them to ensure they are within acceptable size limits.
- Spam content detected. Review and adjust your email content to ensure compliance with spam filters. Avoid excessive use of sales-oriented language and include a clear unsubscribe option.
Missing the inbox? Hit the Target with Abstract
Who said that sending an email was easy? Well, it is, actually, but not quite when part of an email marketing campaign. There, rules change and something as simple as reaching an inbox proves to be impossible (especially, when hard bounces are involved).
The challenge with email bounces is that unresolved issues can quickly spiral out of control, eventually jeopardizing your email address or domain's reputation—potentially leading to their suspension. That's why taking preventive measures isn’t just important: it’s indispensable.
In email marketing, staying proactive is your best strategy for success. With the right measures in place, you can ensure your emails land where they belong—in your recipients' inboxes. And the best part? In Abstract, we're here to help you achieve that.
Visit our website to learn more about our offerings and get your free email validation API straightaway.
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