How to Reduce Email Bounce Rates

Bounce rate measures the number of emails that don’t reach the intended recipient, and acts as a quick and easy way to measure the health of your email marketing list.

In this article, we’ll explain what bounce rate is and why it’s so important to keep it as low as possible, as well as what to do if your bounce rate rises suddenly.

What are email bounce rates?

Email bounce rate is the percentage of messages that don’t reach the intended recipient’s inbox and therefore cannot be delivered. These emails are “bouncing back” to your own inbox.

Bounce rate is calculated by dividing the number of bounced emails by the total number of emails sent, then multiplying by 100 to get a percentage. If you send 5,000 emails and 50 bounce, your bounce rate would be 1%.

The difference between hard and soft bounces

Bounced emails can be divided into 2 different types: hard and soft.

Hard bounces indicate a permanent reason an email can’t be delivered. For example:

• The recipient’s email address or domain name doesn’t exist.
• The recipient’s email contains a spelling error.
• The recipient’s email server has permanently blocked your domain or IP address.

Soft bounces indicate a temporary reason an email can’t be delivered. For example:

• The recipient’s mailbox is full.
• The recipient’s email server is temporarily offline or experiencing errors.
• The email message is too large.
• The email message has been blocked due to its content.

With soft bounces, email marketing platforms will try to resend your emails a few times before giving up. For example, a subscriber may realize they have a full inbox and delete some emails, meaning your email can eventually be received.

Hard bounces cause more issues because email service providers like Gmail and Outlook associate hard bounces with spammy and suspicious sending practices.

Most email marketing platforms (for example, Mailchimp) let you view bounce details, including which addresses resulted in a hard or soft bounce.

Issues with a high email bounce rate

A consistently high bounce rate leads to issues with your sender reputation.

Sender reputation is a score that email service providers give the domain you send email addresses from. A high score shows that you’re trustworthy and increases the chances of your emails landing in a recipient’s inbox, meaning they can be read and actioned.

However, a low score, caused by high bounce rates, increases the chances that your emails will land in people’s spam folders, raising the risk of recipients not seeing your email. In severe cases, email service providers may block your emails from being sent or even suspend your email account entirely.

A good average bounce rate

The average bounce rate for an email campaign is between 1% and 2%.

However, email bounce rate benchmarks can vary by industry. For example, bounce rates are typically higher in the legal and financial sectors. This is because these sectors have stricter spam filters and higher employee turnover, meaning addresses become inactive faster.

If the bounce rate for a campaign exceeds 2%, it means you should look at your email marketing list and the way you collect email addresses to protect your sender reputation.

If it goes above 5%, you should review it urgently.

10 ways to reduce email bounces in your campaigns

The good news is that if you have a high email bounce rate, there are steps you can take to lower it.

Here are 10 ways to reduce your email bounce rate and ensure the right people see your emails.

#1: Clean your email address list

Email marketing lists age over time. People switch email addresses, change jobs, and forget the password to their inboxes.

Removing invalid addresses and inactive addresses from your list lowers bounce rates and allows you to focus on the active subscribers most likely to engage with your emails.

Many email platforms automatically mark and remove invalid email addresses for you, meaning you don’t have to do this manually. For example, Mailchimp immediately removes hard bounces and converts soft bounces into hard bounces after 7 attempts (for an address with no subscriber activity) or up to 15 attempts (for an address with previous activity).

You can also identify inactive subscribers, those who don’t interact with your marketing. These subscribers are likely to become email bounces in the future or mark your emails as spam. You can send them re-engagement campaigns to encourage them to interact again, segment them so you don’t email them as often, or unsubscribe them entirely.

How often should you review your email marketing lists? We recommend cleaning them up at least every quarter, and when you get an influx of new subscribers, for example, after hosting a webinar.

#2: Utilize double opt-in

Double opt-in (or confirmed opt-in) is when a subscriber submits their email address to join your marketing list, and they receive a confirmation email to validate their subscription. It’s the opposite of single opt-in, when a subscriber is immediately added to your email marketing list after submitting their address.

Implementing double-opt in can result in fewer bounced emails as subscribers must confirm their email address is active and accurate. This filters out fake accounts, bots, and mistyped addresses.

Double opt-in also improves your overall engagement, as you’re communicating with engaged subscribers who have actively agreed to receive your messages.

#3: Use email verification services

Email verification services check if an address in your marketing list is real, active, and safe to send to, reducing the risk of hard bounces.

Email validation tools remove fake addresses, disposable email addresses, and spam traps. They also limit role-based addresses, which are defined by a job or title, and typically see lower engagement.

You can upload new emails into your email validation tool or connect the tool directly to your signup forms to check that an email address exists in real time.

#4: Create high-quality, relevant content

Spam complaints affect your email bounce rate.

If enough subscribers mark your emails as spam, this affects your sender reputation. This can cause internet service providers (ISPs) to reject future emails, resulting in email bounces.

The best way to avoid spam complaints is to create high-quality, trustworthy emails. Here are some ways to make sure your messages don’t lead to bounce issues:

• Avoid spammy phrases in your subject line and email content.
• Don’t attach documents or files to your emails.
• Use a consistent sender name and email address.
• Test your emails before you send them to make sure they look and function correctly.
• Use trust signals like reviews, testimonials, and client logos.
• Offer a clear, easy-to-use unsubscribe link.

#5: Avoid buying email lists

Buying email lists is never worth it. Not only does this lead to poor engagement, but it also puts you at risk of breaking the law and results in a high email bounce rate.

Many of the addresses on these lists are out of date, meaning you’re sending messages to invalid email addresses that no longer exist.

Purchased email lists can also contain spam traps. These are email addresses intentionally set up (or dormant email addresses that are repurposed) by anti-spam organizations and ISPs to identify spammers. If you send an email to a spam trap, your sender reputation will be affected, increasing your bounce rate.

The best approach is to build your own mailing list over time with people who have actively opted in to receive your emails.

#6: Authenticate your email address

Authenticating your email addresses before you use them for email marketing campaigns helps keep your bounce rate low.

Email authentication shows major providers that you’re a legitimate sender, increasing email deliverability. It also reduces the risk of cybercriminals spoofing your email address, protecting your sender reputation (it’s also mandatory if you’re a high-volume sender).

There are 3 elements you need to consider to authenticate your email addresses:

• Sender Policy Framework (SPF): Specifies the IP addresses and servers authorized to send emails from your domain
• DomainKeys Identified Email (DKIM): Proves that the message originated from your domain
• Domain-based Message Authentication, Reporting & Conformance (DMARC): Tells servers how to handle any emails that fail SPF or DKIM authentication

It’s important to note that while setting up email authentication will significantly help your deliverability, you also need to keep your email lists clean and send high-quality content.

#7: Implement CAPTCHA and honeypots

Sometimes automated software applications, or bots, can sign up for your emails. There are a few reasons why bots are used, from flooding a victim’s inbox with emails to trying to identify weaknesses in your website.

This leads to a high number of invalid email addresses, which in turn results in email bounces.

You can reduce the risk of bots signing up for your emails by implementing a double opt-in, but there are other things you can do, too.

A CAPTCHA (or reCAPTCHA) asks subscribers to complete a test that is easy for a human, but hard for a bot. You can also implement a honeypot field. This is a fake field on a signup form that only bots can see, and if it is filled in, the submission is rejected.

#8: Don’t use free sender domains

Free sender domains like Gmail, Hotmail, and Outlook may look like an easy way to get started sending emails. But in reality, they can lead to high bounce rates.

As you don’t own the domain, you can’t set up Domain Name System (DNS) records, which results in spam filters viewing your emails suspiciously. You also fail DMARC authentication, meaning email servers may believe your email is spoofing a legitimate domain.

To reduce email bounce rates, it’s better to use a domain you already own or purchase a domain.

#9: Establish a posting schedule

Mail servers track your send frequency and email patterns. If your posting schedule drastically changes (for example, sending 5 emails a week and then nothing for a month), they may start flagging your messages as spam, which affects your sender reputation.

Posting irregularly can also frustrate your subscribers. If you promise to only send emails once a week and then send emails 3 times a day, readers may start sending your messages to the spam folder.

It’s important to be consistent when sending emails. If you want to increase the number of emails you send (for example, during Black Friday), do it gradually rather than all at once.

#10: Monitor your sender reputation

Finally, it’s vital to closely monitor your sender reputation to ensure your emails are always delivered.

There isn’t a definitive way to monitor sender reputation, as each mail server has its own criteria. You can check your status on Gmail and associated platforms by using Postmaster Tools. Check it on Outlook and Hotmail by using Microsoft SNDS.

You can also check if your domain or IP addresses have been blocklisted on Spamhaus or MX Toolbox. If your domain or IP address is blocklisted by an ISP, your emails will automatically bounce or land in a recipient’s spam folder.

Confidently send email campaigns with Mailchimp

We all worry that our perfectly planned campaigns will end up in someone’s spam folder.

Keeping your bounce rate as low as possible is a top way to ensure email deliverability and protect your sender reputation. And that means better campaigns, more conversions, and happier subscribers.

Mailchimp provides peace of mind when planning and implementing your email marketing campaigns. From automatically cleaning hard bounces from your subscriber list to identifying risky addresses using Omnivore, our goal is simple: to make sure your emails get seen.