What Is Email Deliverability?

A Guide for Email Marketers

What Is Email Deliverability article image.

In the age of social media messaging and SMS, email may seem like an almost outdated technology. However, email marketing is still a highly effective form of digital marketing. In fact, 64% of small businesses utilize email marketing to reach customers, and 37% of brands are actually increasing their email marketing budget. 

With all that said, email marketing isn't going to deliver much value if the emails that you send don't ever reach the recipient's inbox. This is where the importance of email deliverability comes into play. To help you improve the reach of your email marketing campaigns, let’s explore everything you need to know about email deliverability, including what it is, how it matters, and five proven tips for boosting email deliverability. 

Recommended: Check out our review of the best email marketing software for startups.

Email Deliverability 101

One of the pros of email marketing is that marketers can track a wide range of metrics to see how their emails are performing, from opens to clicks to conversions. One such metric that is essential to track is email deliverability.

We've put together a comprehensive guide to email deliverability that is sure to help guarantee that as many customers as possible see your marketing emails. You can also check out our short video on the topic below!

What Is the Definition of Email Deliverability?

According to research from Influencer Marketing Hub, only 79.6% of marketing emails reach their intended destination. This means that about one out of every five emails will never end up in the recipient's inbox. 

This percentage of emails that are successfully delivered is known as email deliverability. The higher your email deliverability rate is, the more reach your email marketing campaigns will deliver.

Email Delivery vs. Email Deliverability

Email delivery and email deliverability are two terms that are often used interchangeably. However, there is an important distinction between the two. Email delivery is defined as whether the recipient's mail server accepts the email regardless of the folder that it’s sent to. This means that an email that is sent to the recipient's spam folder would still count as being delivered.

Email deliverability, meanwhile, only considers emails that are successfully delivered to the recipient's inbox. Since this is where you want your emails to end up, email deliverability is the more important of the two metrics for email marketers to track.

Why Is Email Deliverability Important?

To explain the importance of email deliverability, let's go back to the statement that only 79.6% of marketing emails are delivered to the recipient's inbox. This means that the average email marketer is missing out on about 20% of the customers that they should be reaching. That's a lot of lost opportunity, especially when you consider the amount of time, money, and effort that it takes to build a subscriber list.

If you've successfully collected the email address of a potential customer, you want to make sure that they actually see the emails you send. Improving your email deliverability is the key to making this happen.

However, reaching as many subscribers as possible is just one of many reasons why email marketers should strive to boost their email deliverability. When an email is not successfully delivered, it harms the marketer's “sender reputation.” Since sender reputation is one of the factors used to determine email deliverability, the result is a harmful cycle that can potentially impact the effectiveness of your email marketing efforts in a major way.

Factors Affecting Email Deliverability

There are several factors that can affect email deliverability. Some of these factors you will be able to control, while others there's much that you can do about. By controlling the email deliverability factors that you can influence, though, you can improve the rate at which your emails are successfully delivered. With that in mind, here are the top factors that impact email deliverability: 

Email Authentication

SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail) tools are commonly used to authenticate emails. Using these tools to ensure your emails are properly authenticated will improve their deliverability. 

Email Volume

The more emails you send, the more they will be scrutinized by the recipients' mailbox providers. This means that brands that send a large volume of emails are going to have a harder time maintaining good email deliverability than smaller senders. 

Email Content 

When it comes to email deliverability, the content of your emails matters. First, you will want to avoid any suspicious phrases that could cause your emails to be flagged as spam. Phrases such as "free offer" and "no catch" are likely to cause your email to be flagged as spam. You will also want to avoid including any potentially malicious code, such as <embed> tags or JavaScript. Lastly, you will want to make sure that any URLs that you include in your emails link to reputable websites and avoid shortening URLs with a URL shortener. 

Hard Bounces and Spam Traps 

Hard bounces and spam traps are both evidence that an email marketer is not following good subscriber acquisition practices, which can hurt their email deliverability. Having a lot of hard bounces indicates that you are sending emails to a lot of addresses that don't actually exist.  

Spam traps, meanwhile, are specifically designed by mailbox providers to catch and punish poor subscriber acquisition practices. These spam traps are hidden in places where only email-scraping software will find them. If an email marketer is sending emails to these spam traps, then it is evidence that they are either using email-scraping software or purchasing email addresses from someone who does. In either case, their email deliverability is going to suffer as a result. 

Spam Complaints 

Complaints from recipients are another way that mailbox providers go about identifying senders that need to be blocked. This makes it essential to keep spam complaint rates to a minimum. In fact, a spam complaint rate of just 0.1% or higher is likely to impact your email deliverability. 


Engagement is an essential metric for email marketers to track when it comes to gauging the effectiveness of their marketing emails, but it can impact email deliverability as well. If your emails have a low engagement rate, then future emails are less likely to be delivered successfully. 

Sender Reputation 

Mailbox providers use several factors to determine sender reputation, including many of the factors that we've already covered. If your sender reputation is good, your emails are more likely to be delivered. A poor sender reputation, meanwhile, will lead to poor email deliverability rates. 

What Is a Good Email Deliverability Rate?

Email deliverability rates tend to vary from company to company and industry to industry. As a general rule of thumb, though, you want your email deliverability rate to be between 85-95%. Researching average email deliverability rates for your industry will help you determine a more precise number to shoot for.

How to Test Email Deliverability

The best way to test email deliverability is to utilize an email deliverability tool. These tools will enable you to test numerous aspects of email deliverability and measure how your emails are performing. A few good email deliverability tools to consider include: 

  • Mailtrap
  • Sender Score
  • Spamcheck by Postmark
  • SendForensics
  • MXToolbox
  • Glock Apps

5 Tips to Improve Email Deliverability

If your email deliverability rate is lower than you would like it to be, the good news is that there are several steps that you can take to improve it. Here are five effective tips for boosting email deliverability: 

1. Remove Hard Bounces From Your Subscriber List 

A hard bounce occurs when an email is unable to be delivered due to a permanent issue such as an invalid email address, and it's important to remove any of these addresses from your subscriber list. A soft bounce, meanwhile, occurs when an email cannot be delivered due to a temporary issue such as a full inbox. Soft bounces should not be removed from your subscriber list immediately, but they should be treated as hard bounces and removed if they continue to occur. 

2. Authenticate With DKIM and SPF 

As mentioned earlier, SPF and DKIM are both tools that can be used to authenticate your emails and thus boost email deliverability. Ideally, you should take advantage of both of these tools. 

3. Utilize Double Opt-Ins 

One key to boosting email deliverability is ensuring that everyone on your subscriber list is actually interested in receiving the emails that you send. By requiring subscribers to double opt in by sending them a confirmation email, you can ensure that the email address is indeed valid while ensuring that the subscriber did indeed intend to sign up for your mailing list. 

4. Make It Easy to Unsubscribe 

Making it easy for subscribers to unsubscribe from your mailing list may sound counterintuitive. Once again, though, you only want to send emails to those who wish to receive them. A subscriber who wishes to subscribe but can't figure out how isn't likely to engage much with your emails anyway, but what they are more likely to do is file a spam complaint. To avoid this, be sure to make it as easy as possible for disgruntled subscribers to remove themselves from your list. 

5. Avoid Spam Traps 

We've already covered how mailbox providers use spam traps to identify senders that collect email addresses unethically, and it is essential to make sure that you don't fall victim to one of these traps. As long as you acquire subscribers appropriately, though, and avoid purchasing them/using email-scraping software, this is an issue you shouldn't have to worry about.