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The Complete Guide to Open Rates

Kristian Freeman
Kristian Freeman

In this guide, you’ll learn about one of the most important metrics used for measuring newsletter health: open rates.

What are open rates?

Open rates refer to the percentage of successfully delivered emails opened by subscribers. Consider the following example: if your email list has 100 subscribers, and you send an email that’s opened by 50 people over a week, that email has an open rate of 50%.

It’s not uncommon for some emails to not be delivered: for instance, if a subscriber has a custom email server, and it stops working, the email you send to them will bounce: because of this, we calculate open rates as a percentage of successfully delivered emails. If 10 emails bounce from our above example, the open rate then becomes 50 out of 90 (100 subscribers minus 10 bounced emails), or 55%.

What are open rate and click rate, two important mailing list metrics?

How are open rates calculated?

Like many questions around data and statistics in newsletters and email marketing as an industry, this question has a fairly technical answer, if you want the complete story. But to provide a simplified answer: open rates are calculated using tracking images inside of an email.

When an email is sent to a subscriber, a small, often single pixel image is embedded inside of the email. This image isn’t an actual image -- it won’t render a logo or anything inside of the email.

Instead, the URL of the image communicates to the email provider who is reading the email.

For a contrived example, say that I’m subscribed to a newsletter -- my subscriber data is represented as ID #123 in ConvertKit’s database. ConvertKit may then embed an image into the email with the following URL (provided as an example -- not a real URL!):

https://convertkit.com/track?id=123

Inside of the subscriber’s mail client, the image is loaded, and in doing so, the email provider (for instance, ConvertKit) is able to track that subscriber #123 has read the email.

Why does this matter? In recent years, there has been a recent push for more privacy-focused applications and software in the industry. Because of this, many email clients offer features to block images in an email, effectively rendering the open tracking feature of a newsletter provider as useless.

For an extreme case of this, see Hey.com, the email application launched by Basecamp. Hey has taken a hard stance on email tracking, and will both block the tracker (see the below image for an example), and show a notice in the interface that there was a tracker embedded in the email.

Viewing a recent Indie Hackers email in Hey. This isn’t designed to shame IH — the vast majority of newsletters in my Hey inbox look like this!

What is the average open rate for a newsletter?

The average open rate depends on the industry that you’re working in, and what kind of newsletter you’re sending. As a rule of thumb, if you’re sending a more personal newsletter versus traditional email marketing, for instance, a newsletter for your blog versus a weekly outreach campaign for your business, it’s safe to assume a higher open rate.

In the Mailing List Hackers community, we usually tell people that anything over a 40% open rate for “personal newsletters” is quite successful, especially as your list grows past a few hundred people. This isn’t a scientific measurement, but in our experience, that’s a great open rate that many of our members hit with their lists.

On the topic of scientific measurements: there’s been many studies researching open rate percentages across the email marketing industry as a whole. Mailchimp’s “Email Marketing Benchmarks and Statistics by Industry” is a comprehensive look at how each industry approaches both open rates, and click rates. According to Mailchimp, the average open rate across all the industries they measured was 21.33%.

How to improve your newsletter’s open rates

Improving your newsletter’s open rates will be a perpetual task as you grow your list. Here’s a few things to consider as you work on your newsletter that will help you increase your open rates.

How to improve open rates for your newsletter or mailing list

Optimizing your subject lines

Tools like ConvertKit offer A/B subject line testing, allowing you to experiment with more appealing headlines, which can increase the amount of subscribers opening your emails. As you continue to experiment with subjects, you may start to develop a sense of “good subject lines” — your audience will have a particular preference for certain topics and styles, so given a piece of content in an email, you’ll be able to intuit a great, high-performing subject line good for your open rates.

Remove cold subscribers

Your number of subscribers is, simply put, a vanity metric. A more important metric? Active subscribers. If you have people on your list who aren’t reading your emails, they’re known as cold subscribers.

There’s a ton of education in the email marketing industry about “re-engaging” these subscribers — simply put, tactics to getting them to start reading emails again and engaging with your content — but if you find that re-engaging these subscribers doesn’t work, you should just remove them from your list. The math checks out: if 20 of our 100 subscribers are cold, removing them and sending another email that’s opened by 50 subscribers means that your open rate is much higher — 50/80, or a 62.5% open rate.

Conclusion

There’s always more to learn in the world of email marketing and newsletters. If you enjoyed this guide to open rates, consider checking out some of the other content on Mailing List Hackers, and joining our private community, where we host meetups and a chat server for getting feedback and sharing what you’re working on. Learn more about our community here!

Kristian Freeman

I'm a programmer and writer — I also founded Mailing List Hackers! I love to teach, write, and make stuff online.