A/B Email Testing: How to Do it Successfully?

Are you curious about how to carry out A/B testing of email campaigns and automations? Jump into this comprehensive guide to everything A/B testing for email marketing.

Robbie Fitzwater
Updated on

Every email marketing campaign aims to drive strong open and click-through rates to drive maximum site visitors and sales. But improving these metrics doesn’t happen by accident. We get questions about how to improve these all the time. And one of our first answers is test, test, and then test some more (the importance of A/B testing)!

Only by the practice of A/B testing your marketing emails are they going to get any better and be able to make the data-informed decisions that will set your results apart! Creating a feedback loop is the differentiator that separates those high-performing, high-converting, and revenue-driving emails from everyone else’s.

It doesn’t happen overnight and, in many ways, is as much of a mindset as it is a process, so we figured we would help you answer some of those common questions we get most.

  1. What is A/B Testing for Email Marketing?
  2. What are the Benefits of A/B Testing Email Campaigns?
  3. How To Start A/B Test Email Campaigns?
  4. Which Variables Can You Test? 
  5. How to Measure A/B Test Results?
  6. What are You Waiting for? Start Your A/B Email Test Now!

Lucky for you, we have all these answers.

And we put together this comprehensive guide to help you level up your email marketing game. So without further ado, let’s dive in.

What is A/B Testing for Email Marketing?

When we talk about emails, A/B testing is a strategy of testing multiple variables or variations of an email to understand what is working best. 

In other words, A/B testing gives you the insights and data of your email performance. This data enables you to understand which variation of your email is receiving more engagement and which is receiving less. 

It helps you as a marketer to move forward and understand your audience better to drive the actions you want to create. 

There are certain types of ab tests for emails. Simple A/B tests may include testing different subject lines or call-to-actions to know which one is tempting people more to open. 

Alternatively, the advanced A/B tests include testing multiple email formats or templates to identify which one works better in terms of open and click-through rates. 

Moreover, in the world of marketing, A/B email testing is also known as email split testing. 

Now, as we’ve understood what A/B testing for email marketing actually is, it’s time to delve into its benefits. 

What are the Benefits of A/B Testing Email Campaigns?

Testing something on a small scale before making it public is an effective way to achieve an outcome. That is why A/B testing of marketing campaigns comes in handy. Let’s understand the benefits of email split testing in detail. 

It Increases Open Rates

A/B email testing allows you to test the factors that help in increasing your open rate. For instance, you can test your preview text, CTAs, and subject lines to see what resonates with your target audience the most. 

This knowledge of what your email subscribers prefer the most will enable you to enhance your email campaigns. This, as a result, increases your open rates. 

It Improves Click-Through Rates

Similarly, like your open rates, A/B testing enables you to test your email elements like your body text/copy, email design, and your email offer. Testing these elements makes you aware of what your email subscribers tend to click on. 

After performing A/B tests, you can tweak your future email campaigns according to the analyzed data to receive better results. 

It Helps You Gain Valuable Audience Insight

A/B testing email campaigns tells a lot about your target audience. It helps you determine what your target audience likes to engage with and values the most. 

These valuable insights can help you in your overall marketing and content strategy. 

For instance, if your audience engages with a specific call-to-action the most, you can also include that CTA on other platforms too. 

On the flip side, if a certain element of your email is not performing well in terms of conversions and open rates, you might consider dropping it. 

Most Importantly – It Increases Your ROI and Conversion Rate 

As you know, leveraging the A/B email testing method increases your open and click-through rates. This, in turn, directly increases your prospects into paying customers, consequently improving your ROI.

However, to pull that off, you also need to pay attention to your landing pages as well. A landing page is a page that you link in your emails and direct subscribers towards. 

So make sure to optimize your landing pages to their fullest to increase conversions. 

How To Start A/B Test Email Campaigns?

Now that you have an idea of how beneficial A/B testing email campaigns can be let’s find out how to do it successfully. 

While A/B testing marketing emails may seem easy in theory, it can be a little tricky. In order to run a successful A/B testing email campaign, you need to plan and analyze a few things beforehand. Below are the steps you can follow to ensure you are on the right track with you’re A/B testing strategy.

Have a Goal in Mind

Before starting your A/B testing, it is imperative to have an objective in mind. For instance, you need to make a hypothesis, decide what you want to learn about your target audience, figure out which metric to improve. 

Your campaign-level metrics may include: 

  • Conversion rate
  • Click rate
  • Open rate
  • Number or percent of conversions on a specific behavior (Ex: Fill out a survey or form, sign up VIP list, join a preorder list, etc. the sky is really the limit here) 
  • Number of replies – this one is a great way to engage an audience in both B2B and B2C also it really helps prove you are a trusted sender in the eyes of Gmail or any other email service. 
  • Number of calls/appointments booked – B2B
  • Number of people sharing/forwarding
  • Number of people unsubscribed
  • Spam complaints

Pick the Variable You Want to Test

Once you know what you are aiming for, the next thing to do is choose the variable you want to test. The variable components may include:

  • Subject line
  • Call to action
  • Frequency
  • Personalization
  • Timing of the email
  • Images 
  • Target audience
  • Design

Moreover, you need to test a single variable at a given time. This approach may seem a bit slower, but testing one variable at a time will enable you to make more informed decisions. 

Have the Parameters in Place

In the third step of you’re A/B email testing process, you will make the most decisions. While setting up your parameters, you ask certain questions and find answers related to your email campaign. Your questions may include:

  • What should be the duration of the testing phase? Depending on how much data you collect or how fast you can collect it, this is going to vary. As a baseline, it will depend if you have more than 1,000 data points for both test parameters. Then that is a solid population and should be golden. If you can’t build out your data quickly, then 1-2 months may yield the results you are looking for, especially if there is a clear winner in the data collected. 
  • Who is this test directed towards? If you aim to conduct the test within a particular audience segment, ensure that your audience base is significant in size to receive accurate results.
  • How to email split testing? After figuring out which audience segments you need to send the test to, you’ll decide on how to split the test. You can follow several approaches to do so. One way to do this is by performing a 50/50 split. In a 50/50 split, half of your audience receives the control version of your email, and the other half receives the variable version.
  • Which metrics can you use? You’ll have to choose the metrics to receive the data that helps you measure results. 

Run the Test

The final step is to run the test. You can do this by automating the process or following the traditional approach of sending manually. 

Automatically ⇒ You can have you’re A/B test run automatically by using modern email automation software. This is a relatively simpler and easier way to run an A/B test. However, it is used for more surface-level objectives like improving open rates. 

Manually ⇒ The other way to run the test is by splitting it manually. This manual set of emails and the process of manually sending them can be a bit slower but gives you a deeper and clearer insight into the customer data. 

After running the test, make sure to check whether your results are statistically significant or not. You can do this by using any significance calculator tool for A/B spilt testing online. 

Which Variables Can You Test? 

As discussed earlier, you should isolate variables to get more informed results.

But which variable you can test and how to do it are the two questions you must be curious about. Let’s find out. 

Subject Line

The subject line you choose plays an important role in getting people attracted to your emails. It can either make them open your email or simply push them away. That is why one of the essential variables to test is your subject text or line. 

You can write a couple of subject lines to test on a particular segment within your audience. From there, you can gauge which subject line attracted more subscribers and tempted them to open. With this information, you can pick a better-performing subject text and send it to the rest of your target audience. 

However, make sure to conduct these tests every now and then to stay on top of your email game. 


The preheader is the email snippet that displays a preview text of an email. It gives the subscribers a little insight into what the email is going to be about. 

Just like the subject line, the preheader is also a crucial factor when it comes to open rates. One great way to make your preheader fully optimized is by including a high-level summary of your email. 

Again, test out some preheaders on your audience segments to see what’s working and what’s not. 

When your subscribers open your email successfully, your body text, images, CTAs, and links come into play. It’s now time to test whether your engagement and click-through rates are increasing or decreasing. 

One way to do this is by isolating one variable and changing it to see which version of the isolated variable performs better. 

For instance, your call-to-action in email A could be “Hurry Up! Sale Ending Soon,” while you can test the CTA “Sale ending in 6 hours” in email B. Shop Now!.”

Alternatively, you can change the body of your email entirely with a different style and tone to see what’s clicking. 

Moreover, you can also test different kinds of images or infographics in your email if you’re using HTML email format. 

Timing of Your Email

Have you figured out what time of the day or what day of the week your audience is active the most? If not, the A/B test has got you covered. Of course, you have no control over subscribers to open your email. But what you can do is optimize your email schedule to improve conversions.

By conducting an email marketing A/B test, you can identify what time is the best to appear in your target audience’s inbox. Or in other words, what is the best time when they are most likely to open? 

You can choose a segment within your audience and send them emails on different days of the week. This will enable you to identify which day of the week is most appropriate to send your newsletter or marketing emails.

Further, after figuring out the best day of the week, try to test which time of the day your audience responds the most. 

Moreover, you can also test the days against the type of email you want to send. For instance, you can send a product feature on Saturday, your newsletter on Sunday, and your promotional email on Friday. 

How to Measure A/B Test Results?

Your email campaigns will only be lucrative if you understand how to measure results. The variables that we have mentioned above can elevate your sales graphs drastically depending on how you leverage them. 

There are three main metrics that most businesses use to identify their email performance. And guess what? They are nothing new to you. Yes, we are talking about:

  1. Open Rates: This metric measures the no of people that opened your email.
  2. Click-Through Rates: This metric measures the no of people that clicked on the links or buttons provided inside your email. 
  3. Conversion Rates: This metric measures the no of people that actually bought your product or services. 

Now, if your goal is to build brand awareness and receive eyeballs, you should aim for higher open rates. Similarly, if you want to drive traffic to your website, you need to improve your click-through rates. Last but not least, if you want people to buy your services or products, your goal should be to increase your conversion rates. 

What are You Waiting for? Start Your A/B Email Test Now!

The idea that you can set up your email campaign and leave it forever is misleading. The world is changing every moment. That is why you need to keep trying and testing to stay ahead of your competition. 

So keep iterating and keep finding new opportunities to serve your target audience in the best way possible. But always remember to test one variable at a time. You can also try out some other ab email testing best practices to see what works best for you. Happy testing!

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