All about email open rates

Our customers often ask us what 'open rate' means, and whether the open rate they are getting is any good or not. We've put together the following guide to open rates, which you will now also find in the help section of your account.

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 at Campaign Monitor 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 readers 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 (the exception is if they actually click a link). Similarly, people reading your html email without images showing will not be recorded as opens.

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.

Simple chart showing that most industries have average open rates between 20% and 40%

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

Why don't you just give me a number!

So what if you or your clients just have no idea of what is a reasonable open rate? Based on everything we have seen here at Campaign Monitor, 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. If, after all that, you are still interested in seeing specific figures, see the footer for some references you can browse through.

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 Friday 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.

References:

The typical open rates in the chart above were derived from Campaign Monitor's own figures, in conjunction with numbers published by Mailchimp, Bronto and Mailer Mailer.

Posted by Mathew Patterson

20 Comments

  • huphtur
    23rd January

    Where can I find this “Open Rate” in my Campaign Reports?

  • Mathew Patterson
    23rd January

    You will find your open rate listed in the Campaign Monitor reports for a particular campaign as “Unique HTML Opened”.

    The labelling is to distinguish it from the total number of opens, which includes the same person opening the email multiple times.

  • Martin
    24th January

    You just made me feel really good about our 55% rate!

  • Carlos Gutierrez
    31st January

    Do you have any idea of what percentage DO READ the email without displaying images? I.E. if I have an open rate of 40%, can I assume another 10, 20, 30% are reading the email without displaying images?

  • Tom Mollerus
    31st January

    Fantastic article!  How about clickthroughs—do you measure them against emails which reach the inbox, or as a percent of opens?

  • Tom Mollerus
    31st January

    Also, you mention that you track opens by embedding a small image into each email. That’s a commonly-used technique, but I’ve also found that it trips some spam filters by matching their “web bug” rule. Have you considered passing open information not to an image call but to a stylesheet call, which some email clients will request even when they don’t request images?

  • Emailer
    31st January

    Have you considered passing open information not to an image call but to a stylesheet call, which some email clients will request even when they don’t request images?

    If you are coding as you should and considering the ‘lowest common denominator’ then you should only be using inline styles. 

    External stylesheet calls can be ignored by some mail clients - most likely the same ones that are ignoring your embedded image.

  • David Politi
    31st January

    LOVE the Public PHP API.
    Thanks!

  • Dave Greiner
    31st January

    Have you considered passing open information not to an image call but to a stylesheet call, which some email clients will request even when they don’t request images?

    Hey Tom, thanks for the suggestion. Unfortunately some web based email clients such as Gmail strip all style sheets from your email automatically, so that wouldn’t be an option I’m afraid. From our experience and tests with common spam filters, a single pixel image doesn’t contribute anything substantial to a potential spam score.

  • Carlos Gutierrez
    7th February

    Still waiting for an answer to my question:

    Do you have any idea of what percentage DO READ the email without displaying images? I.E. if I have an open rate of 40%, can I assume another 10, 20, 30% are reading the email without displaying images?

  • Dave Greiner
    7th February

    Carlos, unfortunately I don’t have any hard and fast figures on this right now, but I’ve read it can range anywhere between 5 and 15% on average. Of course, this completely depends on the email environment your recipient is using. As far as the estimate goes, I’d be leaning more toward the higher end of that range.

  • Curtis Rushing
    9th February

    In reference to the question from Carlos about “untracked opens”, one way we’ve estimated this is to look at the ratio of recipients clicking without generating an open (“orphan clicks”) and applying that ratio to those customers not clicking.

  • Kevin
    10th February

    I’m curious about this just from a technical point of view.  In the logic that calculates your open rates, what happens when there is no record of the tracking image being requested by the email client but there is a click through record? 

    I work in online marketing consulting and sometimes I advise on email marketing systems.  I’ve wondered about this problem for some time, but I’ve never bothered to bring it up because it’s usually pre-decided by whatever system you use.  If a user has no record for an open but has a record for a click, it seems to me that the business rules dictate adding a record of them having opened the email as well as clicked through, but I don’t believe this is the norm. 

    How do your systems handle this?  With image blocking having become by far the norm, I pay very little attention to open rate except as a trendline statistic anyway, but it seems like if accuracy is the goal then counting people who click and don’t open as people who open would be the correct business logic.

  • Dave Greiner
    10th February

    Kevin, if images are disabled and no open is counted, but a link is clicked, we’ll then add an open for that subscriber too. It’s a very safe assumption to make.

  • Curtis Rushing
    13th February

    I agree that it’s a very safe assumption to add “orphan clicks” to opens.  A high number of orphan clicks may also indicate that you may have a high number of other untracked openers who didn’t click.

  • Vince
    30th January

    “if images are disabled and no open is counted, but a link is clicked, we’ll then add an open for that subscriber too. “

    Is this currently shown in your CM or MM reports - seperately or within overall open stats?
    Thanks

  • Dave Greiner
    30th January

    Vince, these opens are not flagged differently to normal opens and are included in the overall open stats as if the subscriber had simply opened your email (which they have).

  • Kevin T
    22nd April

    Our client has just finished a quite successful campaign over several months with an open rate of 17-59%, average at 35% which considering it was a Government department in the health sector would seem to match up with the above chart be regarded as successful. In our case the material sent was more educational hence did score quite low on spam checks.

    Although we can examine subject lines etc, my question is whether the open rate could have been improved further by adding in sender ID and domain keys. i.e. Providing me even more assurance that the emails arrived in the first place and weren’t stopped by the ISP filters along the way?

  • Nair
    23rd April

    What would be a typical CTR of an e-mail campaign, the above mentioned are open rates is there any specific formula for CTR to the parent website.

    Nair
    http://indianadvertisingreviews.blogspot.com

  • Michael Gass
    21st May

    Very helpful information. Thank you for sharing. I’ve already forwarded this to several of my clients as a resource.

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