The Science Behind Email Open Rates (and How to Get More People to Read Your Emails)

The Science Behind Email Open Rates (and How to Get More People to Read Your Emails)

Post summary:

  • What is an email open rate?
  • Email open rate trends 2006-2017
  • How to increase email open rates
  • Email open rate case study (a 66% increase!)

How do you measure the success of your email campaigns?

The chances are that you measure the success by the number of people who open the mail (email open rate) and the number of people who click on a link (click-through rate).

That’s how I used to measure it.

And while there’s nothing wrong with that, what gets overlooked is that the click-through rate is entirely dependent on the open rate, because unless people open your email, there’s no chance they can click on it!

Therefore, in order to get a better click-through rate, you need people to open your email.

So, how do you get more people to open your email?

There’s a lot of opinions on the web about how to increase email open rates, but I’m only interested in the concrete data behind email open rate success.

The science presented to you in this article will help you get more people to read your email campaigns and increase your email open rates, which in turn positively impacts the overall performance of your email marketing strategy.

But, first…

What is an email open rate?

Before I dive into the data, you and I need to understand this metric. You see, most people consider the open rate as the number of people who open your email.

Sounds logical, right?

Unfortunately, that’s not the case. An email is only counted as opened when one of the following occurs:

  1. The reader enables images in your email to be displayed in the preview pane or in a full view of the email.
  2. The recipient clicks a link in the email.

OK, easy enough. But, how are email open rates calculated?

Email service providers (ESPs) calculate the open rate by taking the number of people who open the email and dividing it by the number of emails sent that did not bounce, i.e. failed to reach the recipient.

For example, if you send 100 emails, and 10 of them bounce, this leaves you with 90 delivered emails. Of those 90 emails, let’s say that 10 are opened. This means that your email campaign open rate is 11% (10 emails opened from 90 delivered).

Emails that are not delivered cannot be opened, which is why this number is not included in the open rate percentage.

How have email open rates changed over the years?

Given that B2B email marketing has been the most popular marketing channel for several years’ and that the average number of promotional emails sent to readers continues to increase, you would think that open rate is on the decline.

However, that’s not the case.

Except for a drop in email open rate between 2013 to 2014, the open rate for email has averaged 22-25% (24.79% in 2017).

Email marketing open rate benchmark by year

This is of course good news as it means that email is still a powerful marketing channel you can use to communicate with your prospects or customers.

Before you get more people to read your emails, you first need to understand where you stand.

How many people currently ready your emails? What is your current email open rate?

This is where industry benchmark open rate reports comes in.

How do I compare to the industry average?

Benchmark reports are important in understanding of how the industry is changing on the whole and you should find out your own benchmark based on your email campaign performance. You should be able to pull this number from your email service provider.

Here’s a look at our own open rates based on an email campaign we ran earlier this year:

SuperOffice open rate and clickthrough rate by country

As you can see, open rates differ from country to country.

How do your own email open rates compare?

In 2017, the average open rate across all industries is 24.7%.

If you have an open rate of 25% or higher, then you’re doing great!

If not, don’t worry. You know your email subscribers better than anyone else. For example, if you consistently reach a 15% open rate, which is below average yet your campaign is delivering results, it’s obvious that you are not under performing even if the “industry average” says you are.

Of course, averages are to be taken lightly. Open rates in the insurance industry, for instance, differ from those in the health care industry. And open rates in Europe differ from those in the US.

Email marketing open rates for North America and Europe

The first challenge you need to work on is getting your email to your subscriber list. It’s no use spending hours crafting a perfectly optimized campaign if it ends up in your readers’ spam folder, is it?

How do I get more emails delivered?

Think about this:

More than 20% of marketing emails never make it to a subscriber’s inbox. That’s one in four emails!

Of course, just like open rate, average deliverabilty rates differ by region.

For example, only 66% of emails reach a reader’s inbox in Asia compared to 86% in Europe.

Email marketing deliverability rates

This makes a huge difference to your email open rates!

So, how can you make sure your emails are delivered to your readers?

Here are a few tips on how you can increase delivery rates.

  • Use double opt-in. Double opt-in means that the subscriber will verify that she wants to receive emails from your business (as required by GDPR for marketers’). You don’t want to send emails to people who don’t particularly care about them; otherwise, they will not read them and lower your open rates.
  • Ask your readers to add you to their trusted address book. By simply asking your readers to add the “from” email address to their contact lists, you can increase the number of emails delivered.
  • Cleanse your email list. If a subscriber does not open an email from you three times in a row, the chances are that she is no longer interested in your company. Gmail and Yahoo Mail are smart enough to understand this so if you continue to send emails to subscribers who do not open them, they might be directed to the spam folder.

The more emails that are delivered to your audience, the better chance you have of getting more people to open them.

How do people read my email campaigns?

The way people read emails can provide key insights in how you create your email marketing campaigns.

For example, the type of device they read it on.

Marketers’ can no longer ignore mobile and tablets. Email open rates from mobile devices have grown by 180% in three years and the percentage of open rates from mobile continues to grow each quarter.

Email open rates by device

And as of writing, 55% of emails are now opened and read on mobile devices (Tweet this!)

Can you guess what your readers do when you send them an email that isn’t optimized for mobile?

They delete it. In fact, 70% delete the email immediately!

And yet, only 11% of email campaigns use responsive design to optimize their email layout.

Have you seen your own email campaign template on a mobile device recently?

If not, you should take a look. If you haven’t optimized your email campaigns for mobile devices yet, now is the time.

When should I send my email campaign?

Timing is important to open rates. To know when to send your email campaigns, you have to know your audience.

If you sell software, most of your customers will be enjoying family time on the weekends. That means sending an email campaign on the weekend will lead to fewer opens, if any at all!

So when should you send your email?

Research by Get Response found that the best day to send emails in order to get the highest open rate is Tuesday.

Email open rates by day of week

Now that you know on which day to send your emails, what about the time of day?

Further research shows that readers are more likely to open emails after 12 p.m. And that 23% of all email opens occur during the first hour after delivery (Tweet this!). After 24 hours, an email’s chance of being opened drops below 1%!

Email open rate by hour of day

As you see, the timing of when you send your email is crucial to the success of your campaign. If you send it on a day when people are less likely to read your email, then you could be missing out on a lot of interested customers.

So, when it comes to sending out your email campaign, Tuesday, after 12 p.m. is your best bet. (Tweet this!)

How do I increase email open rates?

The sender name and subject line of your emails are the most important factors in getting them opened and read.

For example, 64% of subscribers say they are likely to read your email because of who it’s from, and 47% of email recipients open an email based on the subject line.

Top reasons for opening an email

Have you heard the phrase “you should spend as much time writing your headline as you spend on writing the content”?

Well, the exact same phrase applies to your subject line.

A well crafted subject line shouldn’t be the first thing you think of. Instead, it should take time. And you should use research and data to help guide you.

A report by Retention Science found that subject lines with 6 to 10 words deliver the highest open rate, making 8 words an ideal number for a subject line.

Open rate by number of words in subject line

If a subject line is too long, it will get cut off and your reader will not know what the email is about (and could ignore it).

Another reason for opening an email is if the subject line is addressed to the recipient, as subject lines personalized with a recipient’s first name, for example, can lift open rates by 20%!

Open rate with recipients name in subject line

Or if you are feeling super creative, Retention Science found that subject lines with movie titles and song lyrics have an average open rate of 26% (Tweet this!)!

Here’s some ideas for you to start testing with:

  • Subject line #1:Imagine all the people...” got free shipping today!
  • Subject line #2: Gone with the wind? Book your summer vacation now
  • Subject line #3: 10% discount on all products! I’m all shook up, uh huh huh

(OK, they might be a little lame, but hey I tried!)

Are there any words I should use or avoid?

By analyzing billions of emails sent and opened, Dan Zarella of HubSpot was able to find out which words to use and which to avoid in the subject line.

Here’s a look at the findings:

  • Most clicked-on emails include these words in the subject line: “secrets”, “e-sales” and “awesome”.
  • Emails mostly reported as spam included the words “confirm”, “features” and “upgrade”.
  • People are less likely to open emails that include a question mark (?) or a hashtag (#).

Creating the perfect subject line that includes key words proven to increase open rates, and sending the email from a known sender should now be at the top of your to-do list for when you next send out an email.

Email open rate case study

By now, you’re probably thinking:

“Steven, this sounds really great, but does it work?”

And you know what? If I was reading this article, I would be thinking the same thing!

The good news is that I’ve tested the science. And it works!

Earlier in the post, I referenced that the average open rate at the end of 2017 was 24%.

Using the techniques listed above and based on data of more than 99,000 emails sent during the last 10 months,  my average email open rate is 40.9%.

That’s right – forty percent!

That’s 66% higher then the average open rate.

Average email open rates based on email testing techniques

At the very least, these techniques are worth testing so try to implement one or two the next time you send out a campaign.

How important is segmentation?

Earlier this week, I conducted an email campaign test.

In the test, I sent two emails. The first email was sent to a segmented list (based on interest) and the second was sent to my main blog subscriber list.

The subject line was the same.

And the email content was the same.

Upon viewing the results, the main blog subscriber list generated my average response of a 40% open rate.

I was happy.

But, what happened next blew my mind…

The segmented list earned a staggering 94% open rate!


The sad part is that 89% of marketers do not segment their email list.

Perhaps now is a good time to start segmenting your lists.


So there you have it!

I’ve provided the science behind email open rates and the ways you can use the data to make actionable decisions about your email marketing.

Here’s the key points for you to take away and use the next time you send an email to increase email open rates:

  • Use 6 to 10 words in your subject lines to get the best open rate
  • Send your email campaigns during the work day and after lunch
  • Personalize subject lines with the reader’s name
  • Use a recognizable sender name
  • Optimize your email campaigns for mobile
  • Bonus: Segment your email lists

Of course, the best option for you might not be to use any of the above. It depends entirely on what your reports tell you. But you can start with the data provided in this post and use the science to guide you to more get more emails opened.

Now it’s your turn

Before you go, can you let me know your thoughts in the comments section below:

  • How do you measure the performance of an email marketing campaign?
  • How do you increase email open rates?
  • Have you optimized your email campaigns for mobile?

I’m looking forward to the discussion.

P.S. Now you know the science behind email open rates, download the free email marketing checklist to get 12 tips on how to deliver revenue winning email campaigns.


About Steven MacDonald

Steven MacDonald

Steven Macdonald is an online marketer based in Tallinn, Estonia, Steven has more than 12 years experience in the online marketing field and is driven by creating success stories. You can connect with Steven on LinkedIn and Twitter.



about 2 years ago

Awesome article, Steven. Great takeaways. Double opt-in and testing the emotional impact of subject lines are great ways to improve email open rates. Thanks, Niraj (Founder at grexit)


Steven MacDonald

about 2 years ago

Thank you for the kind words, Niraj! Let me know how it works out for you.


Bhavesh Viththani

about 2 years ago

Awesome information.You put summery of so many scientific researches in one article!


Steven MacDonald

about 2 years ago

Thanks Bhavesh! Glad you liked it



about 2 years ago

Interesting statistics and info Steven. What source is the statistic about "Reasons for opening the an email" from?


Steven MacDonald

about 2 years ago

Hi Louise. The original source is from CMB (link:, but that leads to the a report. MakrketingCharts also covered it here:



about 1 year ago

Hi there! I really appreciated this post. I have a question about one of your stats. "For example, 64% of subscribers say they are likely to read your email because of who it’s from, and 47% of email recipients open an email based on the subject line." When I click the link, I go to: I see instead that "31) 64% of people say they open an email because of the subject line. (Source: Chadwick Martin Bailey)" Unfortunately the CMB article is gone. But my question is: how many subscribers open based on who it's from? I'll keep digging, and I wanted to let you know that you need to update your stat/change the link


Steven MacDonald

about 1 year ago

Hi Jenn, thanks for the comment. Great question! The percentage in this article is accurate at 64% (as in 64% open the email based on who it is from). The HubSpot article features a blue chart underneath their comment (#31) that is taken from the CMB study. The chart shows the reasons why people open emails. I think in this case, HubSpot need to update their copy to either "64% of people say they open an email because of who it is from", or to "47% of people say they open an email because of the subject line".



about 1 year ago

Hi Steven, What a great article. I am currently doing research on the effect of personalization on the CTR. Do you think I can measure the effect of a personalized subject line on the CTR? Since it probably will cause a higher open rate, would this lead to a higher CTR as well? Or would you prefer to measure the effect of the subject line on the open rate?


Steven MacDonald

about 1 year ago

Hi Lin, Thank you! There's a lot of research out there that proves personalization in subject lines can increase CTR. I'll be working on a follow up post to this article that covers everything CTR related. Stay tuned!


Joseph smith

about 12 months ago

Hi steven, I run email marketing company we provide B2B email list to the companies to market there product or service. Can you let me what subject line and what pitch should i use to get more leads. Thanks,


Steven MacDonald

about 12 months ago

Thanks for the comment, Joseph. I recommend running a test using two variations to see which subject line generates higher email open rates.



about 10 months ago

Hi Steven, I have a question: 'How to calculate the mail's open rate when we sent a pure-text campaign mail?'


Kate Brack

about 8 months ago

Hi Steven, I'm a content marketing writer for a B2B company that markets industry trade shows around the world. We do a hefty amount of email marketing to get attendees to register, and get exhibitors to showcase their products. This article is full of good insights and links. Thank you. Question: the data seems to be up-to-date but some of the comments are from years ago. Is this an article you continue to update?


Steven MacDonald

about 7 months ago

Hi Kate. Thanks for the comment. Glad you found it useful. Yes, that's correct. I continue to update it based on new data that is published.



about 6 months ago

Hi, thanks for the article. Ive just started experimenting with emails. I sell websites to European clients from South Africa. Web design is very expensive in Western Europe and we are able to offer a world class service at half the price. But calling becomes expensive from SA abroad when you consider the amount of cold calls needed to get some good deals. I was thinking of personalizing each email to look as if it is directly aimed at the specific company. So it doesn't look like a random marketing email that I've banged out to a thousand co's. Would you be able to comment or recommend anything?


Steven MacDonald

about 6 months ago

That's a great idea, Adam. I suggest including personalization in their name, company name and location (city). And, if you have clients from big cities, like Cape Town or Johannesburg for example, then include their logos or quotes in the email as social proof for when you send an email to prospects in those cities.



about 4 months ago

Thanks for the article. It helped me a lot! I have encountered the same problem - people won't read my emails, especially millennials. Was trying everything and in the end of my email adventure, I had a ~45% open rate. Now I am experimenting with communication through Facebook messenger. Open rates are much higher than with emails. I highly recommend to check this out.



about 4 months ago

Hi Steven, Thank you for the great article. I was hoping to use your graph data "open rate benchmark by year" for a presentation with attribution, would this be acceptable?


Steven MacDonald

about 4 months ago

Hi Kristy. Of course, you are more than welcome to use the "open rate by benchmark by year" chart, or any other chart featured in this article.


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