How to Leverage Open and Click Reach Rates in Email Marketing

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For the new year, Webbula is launching a series of blog posts about email marketing metrics. We have a variety of esteemed authors from the email industry lined up to participate and are excited to have Jeanne Jennings, from Email Optimization Shop and Only Influencers, to start us off. 


Previous articles you may have missed:

  • Email as a Conversion Tool: 5 Metrics You Should Be Tracking by Tejas Pitkar. Read now.
  • Inactive Email Subscribers: Measure and Minimize Instead of Reactivating by Loren McDonald. Read it here. 
  • Click-to-Open Rates: The Best Measurement of Email Engagement by Betsy Grondy. Read it. 
  • 6 Ways Customer lifetime Value Can Drive Email Marketing Strategy by Emma Warrillow and Tammi Miller. Read it. 
  • Email Deliverability Guide: How to Interpret Delivery, Clicks, and Opens by Tom Blijleven. Read it. 
  • Email Deliverability Guide: How to Interpret Delivery, Clicks, and Opens by Tom Blijleven. Read it.
  • The Surprising Link Between Major League Baseball and Email Marketing Metrics by Chris Marriott. Read it Now
  • Email Metrics to Replace Open Rates After the iOS 15 Update by Dela Quist. Read it. 
  • Open Rates Aren't Perfect: How to really know if your emails are engaging by Emily McGuire. Read it now. 

Watch the informal discussion about this post here.


If you are an email marketer, you’re likely familiar with the open and click-through rate metrics. But how about open reach and click reach?

Open and click-through rate figures provide insight into how your list engaged with a single email, while open and click reach metrics provide insight into how your list engaged with multiple email messages. Here’s an example. 

Let’s say that you send a series of five email messages to drive registrations for your monthly webinars. Here are your open and click-through rate metrics for the series from last month:

webbula metrics open and clickthrough rate 2021 01 11

These figures tell you how each effort in the series performed; but they don’t tell you how the series as a whole performed. 

What do I mean by “the series as a whole?” The biggest unknown here is what percentage of the list was engaged by the series. 

For instance, if it was completely different people opening each email in the series, then you would have reached everyone on your list at least once (added together, the open rates on all five messages exceed 100%) with your message. But if it was the same people opening all five efforts in the series, then you would have only engaged 35.3% of your audience (the largest open rate of the five messages). 

The truth is likely somewhere in between; open reach will tell you where it falls. 

Click reach works the same way. Did completely different people click – that would be 19.1% (the sum of the click-through rates) of your list that clicked. Or was it basically the same people clicking in each email, which would yield a 5.5% (the largest click-through rate of the three messages) click reach. Or is it, more likely, somewhere in between. 

Here is the reach calculation for this series: 

webbula metrics open and clickthrough reach 2021 01 11

Now we know the answer to how many unique people, what unique percentage of the list, was engaged. A total of 61.7% of the list opened at least one of the five email messages; a total of 11.4% of the list clicked on at least one of the three email messages. We often show reach rates graphically, like this: 


So, what do the open and click reach tell us about the webinar series in the example? 

First, it shows us the power of an email series. In this case, the first email had an open rate/reach of 30.7%; but over the course of all five messages, 61.7% of the list opened at least one of them. Using a series more than doubled the number of subscribers who opened an email and saw the message. 

It also shows us how click engagement can be positively impacted by sending a series, rather than just a single email. Here the initial email yielded a click-through rate/click reach of just 3.1%. Only 3% of the list clicked on the initial email. But after five emails, we see that 11.4% of people on the list have clicked on at least one link – that’s more than three times the number of unique people engaging with the webinar series via a click. 

These reach figures also suggest that it’s worth testing a sixth email – since both the open reach and the click reach increased significantly with the fifth effort. 

So how do you calculate reach rates? The concept is simple; the actual execution is not difficult but can be a bit tedious. 

The whole idea here is to identify how many unique subscribers are engaging with the series. The calculation for the first send is easy; it’s just the unique open and the unique click-through figures. Since it’s the first send, everyone who opens or clicks is unique to this series. 

For the second send, you want to compare the list of people who opened the first email to the list of those who opened the second. You de-dupe and anyone who opened on the second email but not on the first is considered ‘new’ and added to the reach calculation. Here’s a simple example: 


Let’s assume that these 10 people are the list for the sends. Four of these people opened each email, for a 40% open rate on each of the three sends. 

Now let’s get more granular. 

Eric, Amy, Michelle and Lisa opened the first email and since it’s the first email, each is a unique open. They are included in the open reach calculation for the first send, which is 4/10 or 40%. 

Now look at the second send. Eric, Michelle and Lisa, who opened the first send also opened the second send. So they aren’t unique openers for this send. But Lauren is. She opened the second email, but not the first. So we add one to the count of cumulative new openers and our open reach rate becomes 5/10, or 50%. 

When we look at the third send, we see that previous openers Eric and Amy opened this email too. But we also see that Greg and Mark, who had not opened the first or second email, did open this third email. That means we add 2 to the count of cumulative new openers and our open reach rate becomes 7/10 or 70%. 

To get click reach, you would follow this same process using those who clicked on each of the email efforts instead of those who opened. 

As I said, it’s a simple concept; but when you have lists of half-a-million, a million, or more, deduping each effort becomes a larger task. An Excel spreadsheet won’t do it; you’ll need a more sophisticated tool. But it can be done. And it is useful to know what percentage of your list is engaging with your email series. 

Try this with your next email series send and let me know what you learn! 

If you enjoyed this post be sure to look for our future posts in this series on metrics! Sign up for our weekly newsletter to get all the future metrics posts, plus other great content from around the email industry, delivered to your inbox. 


 About the Author

Jeanne Jennings

Jeanne Jennings is a recognized expert in the email marketing industry and a sought-after consultant, speaker, trainer and author specializing in email marketing strategy, tactics, creative direction, and optimization. She helps organizations make their email marketing programs more effective and more profitable.

Jeanne is Founder and Chief Strategist at Email Optimization Shop, a boutique consultancy focused on optimizing bottom-line email marketing performance with strategic testing. She is also General Manager of the Only Influencers community of email marketing professionals, Chair of the annual Email Innovations Summit conference, and an Adjunct Professor in the graduate program at Georgetown University.

Her direct response approach has helped B2B, B2C, government and non-profit clients including AARP, Capital One, Consumer Reports, Hasbro, National Education Association, Network Solutions, New York Times, PayPal, Scholastic, UPS, US General Services Administration (GSA), Verizon, Vocus (now Cision), and the World Bank.

Jeanne is based in Washington, DC, she earned her MBA from Georgetown University (Hoya Saxa!), and she is an avid hockey fan (Let’s Go Caps!).

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