Look at the stats of your latest email campaign, and you’ll likely see something called a “bounce rate”, or “bounces”. This is an often overlooked statistic in email marketing that you really should be paying some attention to — especially if you start to see that number climbing.
This article will explain what an email bounce rate is, how to calculate your own bounce rate, and how to improve that figure for better email deliverability.
What is an Email Bounce Rate?
When you send out an email campaign to your subscribers, sometimes that message can’t be delivered to certain recipients. This can happen for a number of reasons, and when it does, the email is “bounced” back to the sender along with some information about why that message bounced. This information enables your ESP to classify whether this was a “soft” bounce, or a “hard” bounce — in other words, a temporary problem, or a permanent problem.
The number you see in your dashboard is the bounce rate: the percentage of messages sent in a campaign that could not be delivered. Naturally, the lower the bounce rate, the better.
A small bounce rate is nothing to worry about, and it’s pretty much impossible to get your bounce rate to zero. Some people close email accounts, move jobs, domains expire. There are plenty of reasons why your message couldn’t be delivered. But if you see your bounce rates climbing, yes it can be frustrating, but it can also damage your email list.
Downsides of a High Bounce Rate
As an email marketer, your list has what is called an “Email Sender Score” or a “Sender Reputation”. Your score is based on things like open rates, unsubscribe rates, complaints, and you guessed it, bounce rates. After all, a high bounce rate is an indication that your list is stale.
If your Sender Score is too low, your messages are more likely to be rejected by ISPs and email clients. Clients are more likely to mark your messages as spam. Email filtering tools could prevent your emails from reaching inboxes. And in extreme cases, your ESP may issue warnings or even suspend your account if your bounce rates are particularly high. This is because extremely high bounce rates are a sign of bad email management, and bad marketing etiquette.
Two Types of Email Bounces
Email bounces are split into two types: soft bounces, and hard bounces. Your ESP will generally show you how many soft bounces and hard bounces have been recorded for each campaign you send.
What Are Soft Bounces?
A soft email bounce indicates that the email address is valid, but there was a temporary delivery problem. We’re talking things like:
- The recipient’s server was down
- The recipient’s inbox was full
- Potentially spammy or suspicious content was found in your message
- Your message was too large.
Just because this message didn’t make it into the recipient’s inbox, it doesn’t mean your next one will suffer the same fate.
If messages are continuously bounced back from an address, most ESPs will automatically convert that soft bounce into a hard bounce (i.e. it’s assumed that the delivery problem is permanent).
What Are Hard Bounces?
Hard bounces, on the other hand, are assumed to be permanent delivery failures. This is caused by things such as:
- A typo in the email address
- A non-existent address
- An email address that’s no longer in use
Hard bounces should be removed from your newsletter in order to keep your list clean.
What to Do With Bounced Messages
In general, email providers will automatically manage bounced addresses, so you don’t have to worry about that side of things too much.
For example, MailChimp will not send messages to addresses that hard bounce. However, those addresses will still be on your mailing list until you choose to remove them. It’s best to check the documentation of your individual ESP to see how they deal with bounces.
Calculating Your Email Bounce Rate
Calculating your email bounce rate is easy. Simply divide the total number of bounced messages from a campaign, by the total number of emails sent. Multiply this number by 100, and you have your email bounce rate.
As an example: if you sent 1000 messages, and 10 of those bounced, 10/1000 = 0.01. Multiply this by 100, and you have your bounce rate: 1%.
What is a Good Email Bounce Rate?
As a general rule of thumb, a bounce rate below 2% is nothing to worry about, and shows that your list is relatively clean.
If, however, your bounce rate goes above 2.5-3%, it’s time to see what’s going wrong, and try to fix the problem before it gets any worse.
That being said, it’s always worth seeing how your bounce rates compare to others in your industry. MailChimp have released this email marketing benchmarks report to allow for easy comparison across many industries. These include not only soft and hard email bounces, but also average open rates, click rates, and unsubscribe rates.
How To Avoid a High Email Bounce Rate
There are a number of things you can do to ensure your email bounce rate stays within a healthy range.
1. Always Use Confirmed Opt-In
Confirmed opt-in (or double opt-in) is the best way to collect valid email addresses. This is because you’ve asked the subscriber to click on a link in a confirmation message, so you know their email address is correct. Gathering this additional validation also ensures that subscribers actually want to receive your newsletter.
2. Clean Your List Often
Every decent ESP will have in-built features that allow you to easily clean your list. For example, removing inactive email addresses, or removing recipients who have been inactive for a certain amount of time. You can usually choose to set up an automation to remove inactive subscribers, or you can remove them manually every few months.
3. Avoid Scraped and Purchased Email Lists
Importing scraped and purchased email lists into most ESPs is against their terms and conditions. Additionally, these kinds of lists are often extremely low quality, resulting in high bounce rates that could seriously harm your Sender Score. Avoid them at all costs.
4. Run Giveaways and Competitions Carefully
You may think that running a giveaway to encourage people to sign up to your newsletter is a great way to build your list. But most people who want to enter a giveaway don’t want to sign up to your newsletter. Therefore, they often sign up with non-existent, or single-use email addresses that offer you no value whatsoever. If you do use incentives to attract sign-ups, be up front about what you’re offering. Ensure your prizes are highly relevant to your ideal subscribers. And let people know they can unsubscribe at any time.
5. Avoid Free Domain Send-From Addresses
Instead of sending messages from free @gmail or @outlook addresses, you should always use a send-from address at your own domain. This will make it much less likely your messages will bounce, or end up in the spam folder.
6. Authenticate Your Send-From Address
Let email authenticators know your sender address is legitimate by ensuring it is properly authenticated with SPF and DKIM records. Check the documentation of your ESP to find out how to do this.
7. Have a Consistent Schedule
Ensure your messages are expected by both your subscribers and their servers by keeping to a relatively consistent schedule. This will prevent your list from going stale, and will reduce the chance of subscribers forgetting they subscribed, and thereby marking your messages as spam, or submitting a complaint against your address.
8. Use Re-Engagement Campaigns
When subscribers stop opening your messages, try to re-engage them with a targeted campaign that sends tailored messages aimed at getting cold subscribers to become active again. If they don’t respond to your re-engagement campaign, that’s a sure sign they’re ready to be removed from your list in order to keep it clean.
9. Include a Preferences Link in Messages
At the bottom of each of your messages, make sure there is a link that takes subscribers to their preferences page where they can update their email address, and opt in and out of certain kind of emails. This will help you to build a more loyal, up-to-date mailing list that’ll stay relevant for much longer.
10. Keep a Close Eye on Results
Catching bounce rate issues sooner rather than later is extremely important. Leave it too long, and the damage can be difficult to repair. So, keep a close eye on your bounce rates for each campaign you send. Look out for large increases, then do the detective work to figure out what might have happened, and fix the problem before it gets worse.
11. Take Care With Dormant Lists
If you’re about to start sending messages to a large list that hasn’t received a message from you in a long time, be careful. Send messages out in small batches, to different segments of the list. This will allow you to check that bounce rate isn’t too high. If it is, then the list needs cleansing before sending a message out to everyone.
Solving Email Bounce Rate Woes
The key takeaway here is that bounced messages are a normal part of email marketing, but you mustn’t let them get out of hand. Always be vigilant and keep an eye on your email bounce rates each time you check your stats.
Using the information above will act as a good preventative measure to keep your email bounce rates in a healthy range. But if they start to climb above 2% or so, it’s time to take action to protect your sender reputation!
