How Do Email Marketing Companies Track Email Opens?

“How can someone read an email without opening it?”

No, it’s not a Zen koan.

It’s a common question that we get from customers, because it happens.

The fact is, people read your emails, but you don’t get a record of them opening the email.

So how does this happen?

It has to do with how opens are tracked and reported, and how your subscribers use their email programs.

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How Are Email Opens Tracked?

Whenever your email marketing campaigns are sent out, your email marketing software (such as AWeber) adds a tiny invisible image to the body of your email. This is often called a “web beacon” or tracking pixel.

Your email marketing software hosts the tracking pixel. For your subscriber’s email program to load that image, it must contact your email marketing software. When this happens, your email marketing software records an open for that subscriber.

The assumption behind this system is “when the subscriber’s email program loads that image, it’s because the subscriber has opened the email.”

While this assumption is often true, it’s not always the case:

  • It’s possible for a subscriber to read your emails, but for your email marketing software to not know.
  • It’s also possible for your email marketing software to record an open when your subscriber hasn’t actually opened your email.

How can this be?

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How Emails Get Read Without Being “Opened”

Think about your own email program for a minute (whether that’s Outlook, Gmail, Yahoo, or whatever you happen to use).

You’ve probably seen a button labeled “Show Images” or “Display Images” or something similar. Right? It shows up when you open an email that has images in it.

Sure, some email clients have made the jump to turning on all images. And people can tell their email program to always turn on images, or to always turn them on for individual senders. But for many of your subscribers, the images in your email only appear if they click a link or button.

If your subscriber doesn’t click that button? Then their email program doesn’t load the tracking pixel, and your email marketing software doesn’t record an open.

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Why Do Opens “Happen” When The Email Isn’t Read?

As you can see in the example above, sometimes the number of opens your email marketing software records is less than the number of subscribers who actually did read your email.

It’s also possible for the number of opens to be greater than the number of subscribers who actually did read your email, too. Here’s a simple example:

Let’s say your subscriber has told their email program to always turn on images for your emails – perhaps because they’ve done this for all emails, or for all emails from their contacts (and you’re a contact), or because they happen to like and trust your emails.

If they click on your emails accidentally, or if they open them in a preview pane (maybe while scrolling through emails in their inbox), your email marketing software will record an open, even though the subscriber didn’t really stop and read your email.

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How Should You Use Open Rates?

So if some opens are missed, and other ones don’t mean that someone actually read your email, what’s the value in even tracking opens? Or using them to decide if your email campaigns are doing well?

You might think, “there is no value. Tracking opens is pointless.”

If that’s you… I get where you’re coming from. But to me, there’s still value in tracking opens, as long as you’re doing so for the right reasons.

Here are two ways that you can get value from tracking your opens:

1. Measure Relative Performance of Your Emails

OK, so an open rate of 20% doesn’t mean that 20% of people actually read your email.

But even so, knowing that the recorded open rate for a given email is 20% still tells you something.

All of those things that can impact how open tracking works, and skew your open rates? They tend to happen slowly.

Your subscribers don’t all start or stop turning images on all at once, and for the most part, neither do the programs they use to read your emails.

If you send two emails a week apart, if one has a 15% open rate and the other has a 20% one, you probably did a better job on the subject line of the one with a 20% open rate.

I wouldn’t use this to do a one-to-one comparison of two emails sent a year apart – even gradual changes pile up after a while. But for tracking performance over a short period of time? Or tracking how your email performance is trending? Open rates will work just fine.

2. Identify Inactive Groups of Subscribers

If your email marketing software offers it (AWeber does), you can search your list to see who hasn’t been opening any emails from you for a while.

You may want to send this group of subscribers one or more of the following:

  • A reactivation campaign
  • An email asking what you can help with (what do they want to get from you?) – have them reply to you directly or send them to a link to submit a form/survey
  • A special offer

Tracking opens makes sending these messages to the right people easier.

Open For Discussion…

Hopefully this helps you better understand how email opens work.

Do you look at your open rates? How do you use them to improve your marketing or business?

Are there any other metrics that you’d like to understand better? If so, what are they?

Share your thoughts and questions below.


  1. Adrian Jock

    5/13/2014 7:59 am

    Hi Justin,

    I’ve read quite many articles written by you and I appreciate your expertise. However, I don’t agree with the last part of this article (“Identify Inactive Groups of Subscribers”). I don’t see the point in taking any kind of decision regarding the inactive subscribers based on the opens, as if this inaccurate metric is the only one that we can use.

    You know very well that there are at least two metrics: opens – not accurate, clicks – accurate. Why should we recommend the inaccurate one? 😉

    If someone almost always opens my emails (according to the reports ;-)) but never clicks my links, is that subscriber an active one? According to your article, that subscriber won’t be considered inactive and no re-engagement emails will be sent their way. According to me, that is an inactive subscriber.

    In the same time, it is true that some emails don’t include any link. For example, there are bloggers who send by email the full blog posts and there are no links, banners, no call to action, nothing that can be clicked. While such email marketing is not very wise, we can’t force anyone do what we think is right. This is indeed a particular case when opens should be used for deciding whether a subscriber is inactive or not. But this is an exception. Not the main rule 😉

    What do you think?

  2. Justin Premick

    5/16/2014 2:31 pm

    Hi Adrian,

    Thanks for pointing that out. A few things to keep in mind:

    – Unresponsive subscribers can negatively impact your delivery rates for your list as a whole.

    In some cases this is because abandoned email addresses are turned into spamtraps. In others it’s simply a matter of the ISP monitoring whether people seem to want your emails, and then using the data they have on that to decide whether to put future emails from you in the inbox, junk folder, or neither.

    – At AWeber, and at some other email providers, when someone clicks a link, we flag them as having opened the message (even if images are turned off). After all, they wouldn’t click a link if they haven’t opened the email – doing so would be quite a trick. 😉

    So if there’s someone on your list who comes up as not having opened any emails in (for example) 3 months, you know that person hasn’t clicked a link in 3 months, either.

    – I never said opens were more important than clicks… only that opens can be useful.

    Clicks are of course important – except for those marketers who never include links, but as you say, that’s not the norm 😉 – and conversions are even more important.

    To me, what matters (and why I wrote this article) is that a marketer not only can read the metrics in front of him/her, but also understand what each one really is saying and how s/he can use each to improve.

    Thanks again for sharing your point of view!

  3. Adrian Jock

    5/16/2014 3:28 pm

    Hi Justin,

    Thank you for your reply. I agree with everything you’re saying in your reply, but… I hope you don’t mind… I feel that you missed my point. Let me rephrase it.

    Real case: Your user John checks the reports and sees that the subscriber X almost always opens the emails.

    If John reads this article but not my comments, he may conclude, “Well, the subscriber X opened almost all emails, therefore X is an active subscriber and there’s no point in sending a re-engagement email. I am supposed to send re-engagement emails to subscribers who never opened my emails during a certain period of time.”

    My point is this one: “John, in order to decide whether X is an active subscriber or not, forget about opens, check the clicks! If the subscriber X never clicked any link, that subscriber is NOT an active subscriber but an inactive one. Most probably the report was wrong – the technology isn’t perfect” 😉

  4. Dimas Riski Putranto

    5/18/2014 5:46 pm

    Hi Justin,

    Is the reactivation campaign necessary? I think a special offer is more useful than reactivation, it is sound annoying isn’t it?

  5. Justin Premick

    5/23/2014 8:22 am


    Oh, in that regard I think we’re on the same page – if someone is never clicking, and you’re consistently sending messages where there’s value for the subscriber if s/he clicks, then yes I’d call that subscriber inactive. Thanks for clarifying!


    A special offer can be a component of a reactivation campaign. By “reactivation” I’m referring to an overall effort to take inactive/disengaged subscribers and turn them into active readers of your emails again.

  6. Tom Roth

    5/27/2014 9:15 am


    What about people who open the same newsletter multiple times? Do the number of opens reported by Aweber represent the number of individual subscribers who have opened the e-mail (regardless of the number of times opened), or the number of times the e-mail has been opened, even if one subscriber has opened the same e-mail multiple times?

    Tracking the number of opens (which I convert to percentage of subscribers) is important to me because my weekly newsletter has a highly variable number of links each time. Aside from all the “fixed” links that are in every mailing, I may have 6 main content links one week and 40 the next. The number of clicks, therefore, varies wildly from week to week, while the percentage of opens is relatively consistent. I also look at the number of clicks per open to get a better picture of the level engagement.

    The number of opens is also useful when I watch the numbers on a daily basis. I target my weekly newsletter for a Saturday morning delivery. By looking at the number of opens daily, I’m able to see that a certain percentage will open it almost immediatley, a certain percentage will open it sometime over the weekend, and then another large group (those who subscribed using their work email address) will open it on Monday when they get to the office. Having seen this, I can tailor my website posting schedule around when people will visit the website via the newsletter. I also settled on the Saturday morning delivery in part because it performed better for me than Friday night or Sunday delivery, based on Aweber data.

    With the email newsletter being active for over 3 years now, I’ve also found that there are certain times of the year when my open rate dips, so I can schedule more important content around the times when I know the open rate will be higher.

  7. Mark

    5/27/2014 12:53 pm

    Oddball tech question:

    What if the point of my list is to deliver an image to my subscribers (different image each e-mail)? Could I use these images as the web beacon instead of the standard, hidden, single pixel image?

    They are expecting the image, and want to see it, otherwise they would not be on the list. This would not be far from asking them to click on a link, except instead of clicking they just give permission to show the image.

    This is not an idle trivia question; I see a possible use. Is swapping out the wanted image for the tracking pixel possible for each e-mail?

  8. Justin Premick

    5/28/2014 10:39 am

    Hi Tom,

    We track both unique opens (meaning the number of subscribers who opened the email at least once) and total opens (meaning if someone opens it 5 times, that counts as 5 opens).

    Here’s an example from a sent broadcast message:

  9. Justin Premick

    5/28/2014 10:43 am


    No, the tracking pixel is automatically inserted and is non-editable.

  10. Tom Roth

    5/28/2014 10:53 am


    That graph is only available in the higher-level subscription. I have the basic subscription, which only reports “opens”. Would that be total or unique?

  11. Dale

    5/28/2014 12:04 pm

    I only track clicks and conversions and constantly test against what is converting.

    Thanks for the post and clever email. I get a lot of good ideas from your messages.

  12. Justin Premick

    5/28/2014 1:37 pm

    Tom, those are total opens (not uniques).

    Thanks, Dale! I’m glad to hear that.

  13. andy

    6/2/2014 8:42 pm

    Hi –
    Great post.
    I found it when I was searching for an answer to the question of whether hitting “Mark as Read” in an email program (gmail in this instance) would ever result in indicating a message as have being read. Do you know?

  14. Justin Premick

    6/3/2014 12:35 pm

    Hi Andy,

    That shouldn’t result in an open being recorded.

  15. John Jamison

    6/3/2014 2:22 pm

    Great article!