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)

Bonus: I’ve created a PDF that you can download for free so you can read (or print it out) it when you have more time.

Post summary:

  • What is an email open rate?
  • How have open rates changed over the years?
  • How do I compare to the industry average?
  • How do I get more emails delivered?
  • How do I get more emails opened?

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 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.

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 is open rate 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 open rates changed over the years?

Given that 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. In fact, email open rates have continued to climb each year since 2007 (Tweet this!):

Email open rates by 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 much 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 email open rates

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

How do your own email open rates compare?

At the end of the first quarter of 2015, the average open rate across all industries was 22% (Tweet this!)

If you have an open rate of 23% 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 healthcare industry. And open rates in Europe differ from those in the US.

Email open rates by benchmark by region

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 deliverability rates 2015

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. 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 by quarter

And as of writing, 51% 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 rates 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 get more emails opened?

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.

Reasons for opening an email campaign

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.

Email 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%!

Email open rates using personalization 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.


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:

  • 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

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 get more people to open your email campaigns?
  • 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 below 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 ten years experience in the online marketing field and is driven by creating success stories. You can connect with Steven on LinkedIn and Twitter.



about 10 months 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 10 months ago

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


Bhavesh Viththani

about 6 months ago

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


Steven MacDonald

about 6 months ago

Thanks Bhavesh! Glad you liked it



about 5 months ago

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


Steven MacDonald

about 5 months ago

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


Leave a Comment

Sign up to a free SuperOffice CRM trial.

It’s free for 30 days. No credit card required.

Start Free Trial