What is an email open?

An open is a number calculated from your total delivered emails minus the bounces you may have. It is often referred to as a percentage.

How do we register an email open?

The industry standard to register an email open is done by appending a tracking image to the email. It’s usually a 1×1 transparent image that goes unnoticed in the email. Whenever images are activated in the email, the email client requests the tracking image, which our servers register. Then we know that the email was opened.

Another way we are tracking opens is be registering clicks within the email. Whenever the recipient clicks a link in the email we know it was opened as well.

Nice to know

Email clients have done a great job to circumvent these ways of tracking and therefore the open-rate is not very reliable. At best it’s an estimate. Its purpose is to serve a general idea of how well your email performs. For example, email clients with preview panes may display the email with images without ever sending the request to our servers, which prevents us from tracking unless we register a click.

Gmail is cutting emails bigger than 102kb and presents the email with only a part of the email alongside a link to show the full email. We cannot register an open before the full email is shown or the email is clicked.

Furthermore, Gmail is caching and displaying images per default. This means that your images are almost guaranteed to be displayed in Gmail. You are likely to see an increase in unique opens because of this. It also means faster load times because Gmail doesn’t have to request the same image twice. This is a good thing but it also affects our tracking image. As you can imagine, something happens with the open-rate when an image is requested only on the first occurrence. The effect of this is that we are only able to register the first time a recipient opens one of your emails in Gmail.

Is your open rate high or low?

There is almost an infinite number of variables that have an effect on your open rate so you really shouldn’t compare your results to others. Small companies tend to have higher open rates because they reach their recipients on a more emotional level. As list sizes goes up, the open rates typically goes down. You want to establish a baseline for your own lists and work from there.

However, MailChimp has done an incredible job at collecting some numbers for a benchmark reference at https://mailchimp.com/resources/research/email-marketing-benchmarks/. The benchmark sheet is continuously updated so it might be worth bookmarking. Just don’t forget that these numbers aren’t hard and fast numbers but an estimate.

How can you improve your open rate?

That…is a whole chapter in itself and something that every marketer wants to master. I have already touched upon a few subjects in an article about Designing for Emotion in emails and in our Email Marketing Best Practices. I highly recommend you to go take a look because mastering the art of improving your open rates is perhaps the biggest factor in your email marketing.