All about email open rates

Find out what an open rate is, how it is measured and calculated, and whether your open rate is normal or not.

What is an open rate?

Open rate is a measure of how many people on an email list open (or view) a particular email campaign. The open rate is normally expressed as a percentage, and we calculate it as follows:

Total emails opened divided by total emails delivered (i.e excluding any bounces)

So a 20% open rate would mean that of every 10 emails delivered to the inbox, 2 were actually opened.

How do you measure an open?

When each email is sent out, we automatically add a piece of code that requests a tiny, invisible image from our web servers. So when a reader opens the email, the image is downloaded, and we can record that download as an open for that specific email.

It is important to understand that the open rate is not a 100% accurate measure. Recording an 'open' can only happen if the reader's email client is capable of displaying HTML with images, and that option is turned on. So if you are sending text-only emails, there is no way to record open rates. Similarly, people reading your HTML email without images showing will not be recorded as opens.

The only exception is that we do record an open for people who clicked a link in your campaign, even if they didn't download images since we obviously know they read at least some of your email.

Another issue is that your readers may have a preview pane in their email client. That preview pane might be displaying your email automatically (and therefore downloading the images) without the reader ever having to click on it or read it.

So you should never take your open rate as a hard and fast number, because you can never know the true figure. It is much better used as general guide, and as a way of measuring the trends on your email campaigns.

What is a typical open rate?

Really, there is no typical open rate. The rate obtained for any list, or group of lists will depend on how it was measured, when it was sent, the size of the list and a zillion other potential variables. There is no shortage of benchmark numbers out there, but even between benchmark figures you will find big variation in the reported open rates.

So instead of giving a specific percentage, we've come up with the following chart.

Typical Open Rates (%)

There are certainly some broad trends in open rates.

  • As list size goes up, the open rate tends to fall; possibly because smaller companies are more likely to have personal relationships with their list subscribers.
  • Companies and organizations that are focusing on enthusiasts and supporters, like churches, sport teams and non profits see higher open rates.
  • More specific niche topics, like some manufacturing areas, also typically have higher open rates than emails on broader topics.
  • Typically 50% of opens occur in first 6 hours after the email is sent, and about 80% within 48 hours.

Why don't you just give me a number!

So what if you just have no idea of what is a reasonable open rate? Based on everything we have seen, and on the other research out there, the bottom line is this:

If you are getting an open rate between 20% and 40%, you are probably somewhere around average.

Very few lists of reasonable size are getting much above 50% open rates from normal campaigns. Your list may have some specific factors that give you higher rates; if so, well done.

However, don't expect to be getting 80% open rates. People are too busy, inboxes are too full and the measurements are technically limited.

How can I increase my open rate?

There are a ton of elements you can vary to try to entice more of your subscribers to open up your emails. Here are just a few things you could try:

  • Experiment with your subject lines: Try including details about the content of the email right in the subject line, instead of using your standard subject.
  • Send on a different day: Are your subscribers too busy on a Wednesday morning to read your email, leaving it languishing down the inbox? Maybe a Tuesday afternoon email would be welcomed.
  • Get the important content up the top: Remember that many people will see a preview of your email before deciding to open it or ignore it. Make sure your email is recognizable, and that your key points are in the top third.