Volodymyr Written by Volodymyr

How To A/B Test Your Email Newsletters To Blow Up Your Conversions

1. Before you launch your A/B Testing
2. What should you A/B Test in your email newsletter?
3. How to set up goals for email newsletters
4. Metrics to pay attention to when running A/B Test
5. A/B Testing Tools
6. Best Practices

A/B Testing compares two versions of an email newsletter where you have changed one single element to see which version yielded a better conversion rate. It combines scientific methodology and marketing.

Thanks to A/B Testing, you will know what types of strategies are working to create better-performing campaigns. Also, you can use it to ensure that your current techniques make a difference in your conversion rates. Moreover, it significantly increases the level of generated leads, sales, and revenue.

Before you launch your A/B Testing

Before you get started with split testing, you need to do the groundwork for a smooth operation, so you can follow these steps as a guideline.

steps before A/B test email

Step 1. Analyze your previous data

Use website analytics and visitor behavior analytics tools to identify existing strengths and problems areas for your email newsletters. It will provide insight into customer behavior, so you can know which segments you should A/B test. You will also have to track your current metrics to use as a baseline for the test.

Step 2. Make a hypothesis

Creating a split-testing hypothesis is the main starting point for email conversion optimization. When you build your hypothesis, you should make observations about the current scenario, speculate possible reasons, suggest improvements to fix the situation, and explain how you will measure the results. For maximum optimization, create a hypothesis for every element you plan to test.

Step 3. Segment your audience

Depending on the type of email newsletter you want to send, it would be wise to segment your email list because not all of your clients and subscribers will have the same interest and level of interaction with you. You can segment according to several categories such as age, gender, geographic location, industry, website behavior, and many others.

What should you A/B Test in your email newsletter?

When setting up an effective A/B test, you must know what exact element of your email newsletter you want to test. It helps to get accurate results and maximize the A/B test significance.

Here are a few hints on what to test:

  • The subject line
  • A sender (person or company)
  • Call to action
  • Plain text or design email
  • Images
  • Time of sending

These options do not limit your imagination. Depending on your business, you test different parts of your letter. In particular, an online retailer can add or miss the price of goods. Think over your need.

Subject Lines

The first thing you will want to split test is your subject line. After all, it is your secret weapon in getting your subscribers to open your email. You can split test subject lines for numerous things such as length, word order, capitalization, and even the use of or the lack of emojis.

Subject line A/B testing

Through A/B Testing, you can take different approaches to figure out what works best for your audience to increase their open rates. For example, maybe using their names drives up the open rates, while using a statement instead of a question results in a dip.

Email Copy

For the actual email copy of your newsletter, you can experiment with size, content, headlines, and even images. For example, you can test whether email personalization yields better results or if long-form content is preferred over short-form content.

With A/B Testing, you can also choose better placements for your client testimonials and website links. Furthermore, it lets you effectively assess techniques and tones of voice for the newsletter so that you can create a sense of urgency when needed.

Call To Actions

Opening your email is only a first step, so it is imperative to put in your best effort for the next logical step - converting your subscribers. Call To Actions are crucial for that, as they dictate whether someone buys your product or clicks through to a landing page.

So, try varying the color, size, text, and type of button for split testing of Call To Actions. You can also change the design of the social media buttons that often accompany email signatures

email signature newsletter

However, the correct and effective experiment with the CTA button is the most important step to get more conversions.

 Design of the newsletter

First impressions do, to a certain extent, influence your subscriber's actions. However, the poor overall design of your newsletter that doesn't impress your subscriber will not make him take action. But if your design manages to impress them, then you will get better traffic. 

The only way to know whether they will be impressed is A/B Testing of the design. For example, you can experiment with images and text to see which fares better. Or you could try using columns for comparisons. Also, try different placements for different elements in a carefully crafted newsletter. 

A/B test design email

source: Klavio

Finally, in today's age, you should split test the entire layout, style, and template on all devices to ensure that your newsletter displays well on all of them.

Time to send the newsletter

The delivery time of your email newsletter has a significant impact across many metrics, especially the conversion rate. 

Of course, no one knows the best time to send your email to your specific audience, but one of the main benefits of A/B Testing is that you will narrow down the delivery window that works best for them. This way, you will figure out the day of the week, time of the day, and time zone that works best for your target audience.

How to set up goals for email newsletters

For email marketing testing, you have to define why you're doing this. Is it to generate more engagement, leads, and/or sales? Maybe it is to know if your campaigns are working? Or, the most popular, is it to increase your open and conversion rates? 

 The goals could vary from organization to organization. But only after you've defined the aim, you can get started on the process. And the most important thing: when sitting down and setting your email campaign testing goals, you have to be realistic. So, make sure your goals are realistic for your company.

Metrics to pay attention to when running A/B Test

While running the A/B Test, you need to figure out which emails get more people interested in your products. To do that, we've laid out some analytics. These metrics will help you to understand what you should aim to improve in your tests. Here, we dive into what each result means and how to achieve the goal your company has set.

Open Rate

As the name suggests, the Open Rate gives us the portion of people who opened your email. So, for example, if your open rate was 10%, your goal might be to increase it to 15%. Having a better open rate does mean that more people will see what you have to offer from the newsletter. But it doesn't necessarily mean that 5% of your test group will buy or even click through to your product.

open rate email formula

If a newsletter shows a good click rate but isn't bringing in more people, you might need to change bits and pieces of the newsletter and do some more A/B testing.

Click-Through Rate

The Click-Through Rate is the ratio of people who clicked on a link in your newsletter to the people who viewed your newsletter. 

 The CTR is an important analytic that you need to keep tabs on, as it brings in more people to view what you have to offer. However, even though having a high CTR means more people will know your product, the increase in conversions might not happen.

 For the most part, having a warmer color palette, a welcoming message, or something that attracts the attention of your target audience will help boost your open rate and click-through rate. 

Email CTR formula

Click baiting is one way of doing so, but we advise you not to promise what you can't offer or lead the audience in a wrong way.

Response Rate

The Response Rate is the ratio of people who responded to the email or took part in an offer to the total number of people in a sample. The greater the response rate, the better you can improve your database and amplify your engagement with people.

 To improve the response rate, you can use, for example, a limited-time discount code for those who received the newsletter or a short survey inquiring about the products they might be interested in.

Conversion Rate

The Conversion Rate is the main analytic that shows your email newsletter performance. A/B Testing improves the conversion rate and, as a result, maximizes your sales. To calculate your email conversion rate, check out this article with a detailed formula and explanations.

Conversion rate formula

The goal of each newsletter is to bring in as many customers as it is possible. However, despite the high CTR, people will not convert when the message in the newsletter and the message on your site don't interest them. So, if the conversion rate is low, you need to tweak and play around with the newsletter. 

 Remember, it should contain a compact version of your message that does not stray from your product. If a person is interested in your product and clicks the newsletter link, they expect to see similar products on your website. 

 If your website has a different tone than your newsletter, it will deter them from associating with your company, which won't help increase the conversion rate. 

A/B Testing Tools

There are numerous A/B Testing marketing tools available right now that help you run these tests. First, define the automation which will do the job for you. For example, it should take your entire list of subscribers, split them into two groups and send letters to each of them. Better to test at the same time, on the list of the same interest. Another way, you will not get accurate data, as it will be affected by time difference and specific features of a target group. 


MailChimp has a built-in tool called "A/B Split Campaign" that lets you pick a sample from your list of subscribers and just run the test on them. After selecting a percentage of people you want to test (MailChimp recommends between 20%-50%), you choose the metric and timings. And voila, you're done! This tool by MailChimp not only informs you which variation worked the best but also sends the winning variation to the portion of your subscribers who didn't receive the test.

MailChimp A/B test

Campaign Monitor

Using the Campaign Monitor's A/B Testing Option, you will get to fiddle around with their customizable email templates. You can select the type of test you want to run, email content, and the subset of your list you want to run the test on. You also pick the test settings as well as the method through which the winner will be selected. Furthermore, even while the test is in progress, you will be able to monitor the results with their A/B Test Report.

Campaignmonitor A/B test


Through SendGrid's tool, you can test up to six different variations for your A/B test campaign. Alongside the usual test, sample size, and winning criteria, you can also pick the test duration, from between thirty minutes to 24 hours. After it decides the winner, you have the option of choosing whether to send that version automatically or to pick the version manually.

Sendgrid A/B test

Kissmetrics A/B test significance

A successful A/B test has to be statistically significant, and Kissmetrics' A/B Significance Test calculates that for you. This tool is different from the other tools mentioned above in the sense that rather than running the test for you, it tells you if the changes you make will have a significant statistical impact on your conversion rates or not. The calculator tells you the difference in conversion rates, whether the changes will yield a higher rate and if that in itself is statistically significant.Kissmetric A/B testing

 Sample Size Calculator

There are many sample size calculators available from different brands. These calculators calculate the minimum sample size required for each version of your test based on your audience. They help you increase your confidence level to see the desired change in your conversion rates. Some split test calculators even tell you the total duration you should run your A/B test for.


Best Practices

Measure one thing at a time

While performing the A/B test on newsletters, we suggest that you send out a newsletter at random while only changing one detail, maybe a different color palette, a bolder headline, another picture, and so on. By doing this, you can examine how each change affects how people interact with your newsletter.change one thing for A/B test email source:  Mailjet


You can study what helps get more clicks and ultimately more conversions to your websites. However, if there are too many differences between the newsletters, you can't pinpoint what improved or diminished your sales.

Prioritize your A/B test

Prioritizing your A/B test helps your company have a clearer vision of what changes your company wants to make, what it expects from the change, and what future tests would look like. 

According to experts, prioritizing removes emotions, helping you and your team to make an informed decision. While prioritizing, there are many factors to keep in mind, from the ease of implementation to how noticeable the change is and even adding important data and removing distractions from your newsletter. 

There are various models for prioritizing the A/B tests: PIE framework (Potential, Importance, and Ease), ICE Score (Impact, Confidence, and Ease), ICE Version 2 (Impact, Cost, and Effort), and so on. Of course, the same prioritization won't work for every company, so the best model depends on how your company runs.

Analyze Data

It's more important to analyze the data received and tweak your variations accordingly. For example, if a test is getting fewer clicks than the previous rate, you should explore why it didn't do as well and try to change to improve the conversion rate. 

While analyzing the data, compare how it's faring over the goals you've set. And, even if the test isn't doing well in the beginning, don't end it prematurely. Instead, run your test for at least a week, so you have a bigger sample size. 

Aside from the number of clicks the change brings, you also need to keep track of customer engagement, from sign-ups to registering for a free trial and how much traffic the site gets. You can improve your sales if you analyze your data and make changes appropriately.

Make sure you have enough data to run a statistically significant test

If your current conversion rate is 15% out of 100 people, 15 people may buy your product, giving an apparent conversion rate of 15%. However, if the sample was more significant, let's say 100,000 people, it's unlikely that 15000 people will have bought your product. 

With a more extensive set of data, the data will shift towards its actual value. So, having enough data to run a statistically significant test will help you analyze the data better.

Run your tests simultaneously

One essential part of A/B Testing is running your tests simultaneously. When two different instances of the same newsletters are being compared, they should be exposed to the same conditions. Many factors, such as your company's growth, demand, products quality, and others, with time, are changing. If the tests are run simultaneously, then the factors listed above will not be influencing the results.

By running A/B tests, your company can develop its optimal marketing strategy. Because it can make a difference, it can help your company accomplish its marketing goals. However, it would be best to keep in mind that you have to plan your A/B tests.


The digital marketing world is constantly evolving. So naturally, new marketing techniques are on the rise.  Every internet marketer knows the secrets of a successful online campaign: know your audience, use best practices, and test, test, test. A/B testing is crucial when it comes to newsletters. Follow our simple pieces of advice of launching A/B testing the newsletter based on personal experience.




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