Hard Bounce vs. Soft Bounce: Email Delivery Troublemakers

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Karolina Petraškienė
Content Marketing Manager
Reading Time: 5 minutes

Hard bounce, soft bounced emails, spam—these all are keywords for poorly performed email campaigns. These troublemakers can spoil not only your email campaign results but your sender reputation as well.

Keep reading and learn how to distinguish hard bounce vs. soft bounce, correct issues you might have with your email delivery, and prevent your emails from bouncing in the first place.

What Is An Email Bounce?

What does it mean when an email bounces? Put simply, an email bounce’s definition is when the recipient’s email server rejects your email message. It means that your message hasn’t been delivered, and the email server sends it back to the sender.

The bounce rate indicates how healthy or stale your mailing list is. It has a significant impact on your sender reputation and is one of the most important email marketing metrics that you have to monitor your email marketing.

There are two different types of email bounce—a ‘soft’ bounce, and a more severe ‘hard’ bounce. Let’s look closer into the differences between them.

Soft Bounce vs Hard Bounce in Email Marketing

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What Is A Soft Bounce?

A soft bounce is an email that hasn’t been delivered to your recipient because of temporary, resolvable reasons. Soft bounces might occur because the size of the email is too large, the recipient’s inbox is full, or the email server is down.

In these cases, email service providers resend the email e.g., Omnisend tries to reach the recipient eight times over twelve hours, giving you time to address the problem. Most of the time repeated and unresolved soft bounces are eventually converted by your email provider into a hard bounce.

So while a soft bounce is a problem that needs to be solved, it isn’t dangerous to your sender reputation until it becomes a hard bounce.


What Is A Hard Bounce?

A hard bounce is an email that is sent back due to permanent, unresolvable reasons. While the causes of a hard bounce are varied, most of the time the recipient’s email address is invalid or no longer in use because:

The biggest, most important difference between soft vs hard email bounces is that a hard bounce can damage your deliverability rates and sender reputation, putting you at risk of being treated as a fraudulent email sender.

Having this status will spoil your email deliverability and is something to be avoided at all costs.

Learn more about email deliverability and sender’s reputation here: Improve Email Deliverability: Common Issues and Best Practices

How to prevent email bounces

While there isn’t any known way how to fix already bounced emails, the best thing you can do is effectively build your list following best practices, and maintain it with proper list hygiene.

This way, you can be sure that your contacts have given the proper consent, are interested in your brand, and are active subscribers. Prevention is the best medicine, so take steps to proactively prevent your emails from bouncing in the first place.

That said, some emails can slip through the cracks, so let’s look at the reasons why hard bounces can occur.

What Are The Main Reasons For Hard Bounces and How Does it Affect Deliverability?

There are several common reasons for email hard bounces and they affect deliverability in different ways. These include:

  1. As a sender, you use free email services like Gmail, Yahoo, or AOL. To reduce deceitful emails, many email service providers have changed their DMARC policies. According to this policy, your emails will not pass authentication and will be bounced. If you are an ecommerce business, you should use an email with your private business domain ([email protected]).
  2. Your list is out-of-date. If your mailing list was built several years ago and you decided to use it only now, don’t be surprised by a high bounce rate. Your subscribers have probably changed their emails, forgotten about you, or are no longer interested in your content. In this case, you should delete users who have been inactive for months.
  3. You purchased or rented an email list. When you build an email list organically, you acquire subscribers who are interested in your brand. When you purchase or rent a list, you don’t. These lists often include old, inactive, and spam trap email addresses that cause high bounce rates and blacklisting. Never purchase or rent an email list! 

    Omnisend’s Terms of Use do not allow you to use purchased or rented lists. If you use an email provider that allows these kinds of lists you are putting your email program at risk. 
  4. You suffer from typos. If your subscriber list is brand new but the bounce rate is high, the problem might lie in the way it was built. People tend to mistype their emails. So you can skim your contacts and check for simple mistypes like @gnail.com, @yahoo.con, etc. Use email verification to ensure email grammar and validation.

    Another way to control this by using a double opt-in method after signing up. This way, you will be sure that the address you are marketing to is functional. Double opt-in lists have a much higher engagement level. By using this method, people cannot sign up with fake email addresses; they have to be valid to opt-in.

It’s also important to allow for an easy, hassle-free unsubscribe somewhere in your emails—it’s better to cut uninterested contacts loose rather than make them irritated enough to mark you as spam.

If your email goes to SPAM, find the reasons here.

What is an Acceptable Bounce Rate for Emails?

The number of bounced emails is directly related to the quality of your contacts list. A low bounce rate (up to 1%) indicates an engaged, well-maintained list populated with real and active subscribers who want to hear from you.

The industry standard for email hard bounces is less than 2%. If you start to go above that figure in your email campaigns, you should keep a close eye on things and make sure it doesn’t continue to climb. If your bounce rates get up over 5% then you might have a serious problem with your list that should be taken care of.

There are several ways to improve the hygiene of your email lists and get your bounce rate back down to an acceptable level. You can find out more about that here.

Key Takeaways

An up-to-date email list is crucial for your email marketing strategy.

High hard bounce rates have a significant negative impact on both the sender’s reputation and email deliverability rate. Using email marketing, you should strive to keep your bounce rate low, ideally under 2%—the lower it is, the better.

Email service providers, including Omnisend, help you to monitor the list’s status throughout email campaigns by measuring deliverability, bounce rates, and unsubscribes to give you a basic understanding of the welfare of your contact list.

It all begins with the health of your list, so make sure it is built with opt-ins and complies with the rules of your provider, as well as with relevant regulations like GDPR.

At the end of the day, use email best practices to build your list, let uninterested contacts freely unsubscribe to focus on quality, not quantity, regularly check and clean your list, and you won’t have any trouble!

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Karolina Petraškienė

Karolina is a writer, content marketer, and email enthusiast at Omnisend. When she's not curating articles, you can find her in the woods challenging herself in hiking boots or off-roading her bike.

Further Reading:

11 Reasons Why Your Email Goes to Spam
Email Deliverability Guide 2021: Common Issues and Best Practices
sender reputation warming cover
How to Use Sender Reputation Warming for Better Email Deliverability

Join the Conversation


    1. Hi Debora,
      You can segment out emails who have become unsubscribed because of bounces.
      – Karolina

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