Everything to know about email deliverability

As you learn about email marketing, you’ll find countless tips and best practices for making sure your email is attention-grabbing, compelling, and optimized for the goal of your marketing campaign.

Before you get into all of that, though, you need to make sure your email actually ends up in your audience’s inboxes and not their spam folders. 

What is email deliverability?

In short, email deliverability is how consistently your emails reach your audience’s inboxes. 

Much of this is related to spam. As you’ve seen in your own inbox, internet service providers (ISPs) and email service providers, from Outlook to Gmail, have criteria and clues that they look for when an email comes in to determine if it’s safe to go in the inbox or if it’s likely spam, in which case they send it to the spam folder.

There are technical aspects of email deliverability, too. Emails that are too large might not be delivered, for example. Strong email deliverability means that you have practices in place to ensure that as many of your messages as possible will reach recipients’ inboxes.

This is instrumental in email marketing because if your email deliverability is poor, fewer people will see your expertly crafted, compelling emails. That means less exposure to your brand, fewer clicks, and, by extension, a less profitable email marketing program. 

According to Email Tool Tester, the average email deliverability rate in 2024 is about 83%, meaning about 17% of emails don’t reach recipients’ inboxes. According to Validity, the average revenue per email is $.10. This means that for every million emails you send (such as sending 100 emails to your list of 10,000 recipients), you can expect to miss out on $17,000 in revenue. If your email deliverability is lower than the average, you’ll miss out on more revenue.

What is a good email deliverability rate?

When you look at email deliverability as a performance metric, you’ll see the percentage of your emails that reach the recipients’ inboxes. The higher, the better, of course, but what’s a strong email deliverability rate to aim for?

As we noted, the global average is around 83% in 2024. A strong deliverability rate may vary based on your industry or other factors, but Email Tool Tester offers these benchmarks:

• Email deliverability above 95% is excellent.
• Email deliverability above 89% is good.
• Email deliverability below 80% is poor.

What factors impact email deliverability?

The first step in strengthening your email deliverability is understanding the factors affecting your deliverability rate. Here are the key factors to watch.

Sender reputation

Email deliverability largely depends on whether the ISP trusts that your emails are safe and ethical, not spam. This comes down to your sender's reputation. ISPs compile and track a sender reputation score for you based on factors like the number of recipients who mark your emails as spam.

A sender score is on a scale of 0-100, and according to Validity, a sender score over 80 is considered good. Your sender reputation data isn’t usually available to you, but there are tools you can use to check it, like Google Postmaster Tools or Validity Sender Score.

Email authentication

Email authentication is a process that allows ISPs to know that the domain you claim to be sending your emails from is accurate. Spammers sometimes mask their domain to pretend they’re sending from a more reputable domain. Some authentication processes allow ISPs to verify your domain, such as DKIM (DomainKeys Identified Mail) and DMARC (Domain-based Message Authentication, Reporting, and Conformance). These have become more critical with the 2024 Google anti-spam update and the similar 2024 Yahoo anti-spam update.

Engagement metrics

ISPs want to make sure they’re opening the door for messages their customers (your recipients) actually want. They do this by looking at specific engagement metrics for your prior emails, like open rates, click-through rates, bounce rates, etc. If these rates are very poor, it tells the ISP that you’re likely sending many emails to people who don’t want them.

Certain email content and sending practices

Along with the major factors above, aspects of your emails’ content and sending practices affect deliverability. For example, an easy-to-find unsubscribe link, especially in your header, helps with deliverability. ISPs may also flag your emails as spam if you use excessive images with little or no text or if you use certain subject line styles that are common among spammers, like all caps and excessive symbols and special characters.

This isn’t an exhaustive list, as ISPs don’t publish all of the ways they filter out spam, but these are the core factors that will impact your email deliverability.

Best practices for optimizing email deliverability

Strengthening your email deliverability allows you to make sure that all the hard work you put into your email marketing will pay off as much as possible, so start incorporating these best practices into your email marketing.

1. Create relevant and quality content

Engagement data will impact your deliverability, and the best way to improve your engagement is the old-fashioned way: with engaging and relatable content. 

Send content that is interesting to your audience, well-designed, and well-written. Be sure to segment your mailing list into different audience segments too, like segments for certain age groups or interests, so you can send emails that are relevant to each group. Interactive content is also a great choice because it garners over 50% more engagement than static content.

2. Clean your email list

Sending emails to people who don’t want them will lower your engagement rates and put you at risk for more spam complaints. When it comes to email lists, think of quality over quantity and aim for a clean list with as few inactive subscribers as possible. You can do this by making it easy for users to unsubscribe when they wish. You can also send re-engagement emails to users who haven’t opened your emails in a while, asking if they’d like to stay subscribed.

Email list hygiene starts with prevention, too. Only add subscribers to your list who have consented to subscribe, and make sure they confirm their subscription via email. Don’t automatically subscribe to every email address you find, and avoid buying email lists.

3. Avoid spam traps

A spam trap is a clever trick that ISPs use to root out spammers, much like a hidden spy. Spam traps are email addresses that ISPs have created, and they don’t subscribe to any mailing lists. This way, they know that anyone who emails that address is using a purchased list, so if you email a spam trap, they’ll categorize you as spam. 

The best way to avoid spam traps is to only send mail to people who purposefully subscribe to your mailing list and not to use purchased lists, or email addresses you find on the web.

4. Keep your bounce rate low

In email deliverability, a bounce is an email that fails to reach the recipient. Some bounces are called soft bounces, temporary technical issues that prevent the email from reaching the recipient. This could happen if the recipient’s inbox is full or their email provider temporarily has issues. 

But there are also hard bounces: a failure that will happen every time you try to send to that email address. Often, it’s because the email address isn’t valid or doesn’t exist. If you keep sending to these email addresses, your bounce rate will be high, damaging your email deliverability, so remove any email addresses that return a hard bounce.

5. Mind all legal compliance requirements

To help curb spam, several governments and organizations have laws and regulations with anti-spam rules you have to follow. If you aren’t complying with all of these requirements, it can hurt your deliverability or leave you vulnerable to legal consequences.

The most notable of these regulations is the CAN-SPAM Act, a US spam prevention law. It includes several steps for businesses to follow, like using accurate sender information, disclosing when a message is an ad, using non-deceptive subject lines, including your location, offering a way to unsubscribe, and honoring opt-out requests promptly.

The GDPR is also an important regulation if any of your recipients are in the European Union. Its email requirements include only emailing people who have actively opted in (instead of emailing everyone who hasn’t opted out), using data protection practices, being transparent and non-deceptive in all aspects of your emails, allowing recipients to request that you delete their data, and responding to deletion requests promptly.

Email marketing tools to improve email deliverability 

• MX Toolbox: Tracks and shows you information about your sender reputation while also screening for any ISPs that have blacklisted you, screening your emails for spam-like practices, and more.
• SpamCheck: Analyzes your sender reputation and gives you a ranking of 0-5 (the lower your number, the better your sender reputation is), along with detailed recommendations to improve your score.
• GlockApps: Conducts advanced inbox placement tests along with spam testing and authentication testing, showing you real-time alerts for deliverability issues, too.
• NeverBounce: Analyzes and cleans your mailing lists to remove any invalid email addresses.
• Google Postmaster Tools: Provides insight into your sender reputation and email deliverability directly from one of the major ISPs.‍
• Mailtrap: Uses a safe testing environment to test out email addresses and remove invalid email addresses before you ever send them a hard bounce.