How to Do A/B Testing for Your Email Marketing: A Comprehensive Guide

On February 13, 2024
6min read
Denys Kontorskyy Technical Content Writer @Mailtrap
This image is a symbolic graphic representation of A/B testing for the article that covers the topic in detail.

In a world teeming with social media and video content, it’s easy to dismiss email marketing as an obsolete strategy. But with 3.9 billion active email users worldwide, email marketing is still alive and kicking. However, effective email campaigns are the real challenge. The key to getting positive results from email marketing? A/B testing. 

What is A/B Testing in Email Marketing?

A/B testing, or split testing, is a “performance tuning” process in email marketing where two versions of an email are compared to identify which one performs better. This technique involves the creation of two distinct versions of an email. Each version is slightly or substantially different, depending on the variables you choose to test, such as email design, subject lines, call-to-action placement, or even send times.

Once these versions are ready, they are sent to different subsets of your email list. Each email plays its part, engaging with recipients and prompting responses. The performance of these emails is then tracked and analyzed with key metrics.

Sounds simple, right? Well, it is, but it’s also a bit more nuanced than that. Just as a beautiful garden isn’t grown by merely planting a few seeds, successful email marketing isn’t achieved by simply sending out a couple of emails.

Why does A/B Testing Matter?

A/B testing is not just a “routine activity” but an essential tool for making informed decisions about your email marketing strategy.

A/B testing meme
Source: www.meme-arsenal.com

The significance of split testing lies in its ability to uncover the most effective way to communicate with your audience, driving engagement and fostering desired actions. By allowing marketers to compare two different email versions of an email and recognize which one performs better, A/B testing eliminates guesswork and paves the way for data-driven decisions that can drastically enhance your email campaigns’ open rates, click-through rates, and conversion rates.

Furthermore, the insights gained from A/B testing extend beyond immediate email campaign optimization. They provide knowledge about your audience’s preferences and behaviors, informing your broader marketing strategy. With each test, you’re not merely fine-tuning an email but building a more compelling and effective marketing message. 

A/B Testing Idea Examples

The beauty of A/B testing lies in its adaptability. From email subject lines to design elements, you can test many variables to optimize your email campaigns:

📝 Testing Subject Lines is a must since it’s the first thing a recipient sees, making it a critical factor in determining whether your email gets opened. Testing different subject lines can help you understand what kind of language, tone, and even email copy length resonate most with your audience. For example, you can compare subject line length or question-based subject lines to statement-based ones. 

“Need a holiday? Pick one of our new vacation deals.”

“New holiday deal made for you.”

🎨 Comparing Email Layouts and Designs of your emails can significantly impact their readability and engagement. Through A/B testing, you can determine which templates and visuals work best for your audience. This could involve testing different formats (‌plain text email vs. HTML email), layouts (single column vs. multiple columns), and visual elements (images vs. gifs vs. emojis).

👆 Evaluating the Call-To-Action Button is the gateway to conversion. By testing different versions of your CTA button – such as its color, size, text, and placement – you can optimize it to drive maximum clicks.

👤 Experimenting with Personalization can be a game-changer in email marketing for small business. Whether it’s using the subscriber’s name in the subject line or tailoring the email content to their preferences, A/B testing can provide insights on how to personalize your emails for better engagement effectively.

Whatever idea you come up with, the ultimate goal remains the same: to continuously optimize your email design and content for enhanced engagement and a reduced risk of unsubscribes.

How to Do A/B Testing in Email Marketing

Now that we have covered the why and what aspects, let’s delve into the “thought process” of the how.

Step 1: Set a Goal

Before plunging into the technical aspects of A/B testing, starting with goal setting is crucial. Identify what you wish to achieve through your email campaign – are you aiming for increased email open rates, improved click-through rates, or a boost in conversions?

It might be a specific metric you’ve been struggling with or an area you believe has the potential for even better results. The goal you set will steer your entire testing process, so it’s important to establish both a clear benchmark – your current performance level – and a desired outcome – the improvement you wish to see. 

Step 2: Form a Hypothesis

The second step involves developing a concrete hypothesis. Once you have a clear goal in mind, the next task is to pinpoint the variables you wish to test. After selecting the variables, form a hypothesis about how changing this specific element might impact your chosen metric.

For example, if you’re focusing on the open rates and testing your email subject lines, your hypothesis might be something along the lines of: 

“Including the company name in the subject line will lead to a marked increase in our open rates.”

If the focus is on the conversion rates and you want to test the copy of your email template, your hypothesis might be:

“Including a landing page link and the sender’s name in the signature can establish a personal connection, thus boosting conversion rates.”

Step 3: Do the Testing

After setting up versions A and B of your email, based on your hypothesis, it’s time to send them to your subscribers. Read our in-depth email marketing guide to find out how to ensure that this is a high-quality list that truly represents your target audience.

Run the email marketing campaign for a sufficient duration, considering variables such as weekdays and optimal times to ensure accurate results. Once the test run is over, the crucial part is to analyze the results.

Dig into the data to determine which version of your email performed better. Was your hypothesis validated, or was the result contrary to your expectations? Each outcome provides valuable insights.

Tweet on the importance of A/B testing
Source: twitter.com/theandreboso

Step 4: Implement the Findings

The “tricky part” is over. Now it’s all about applying your testing results and deciding whether to implement the winning email version in your future campaigns.

Remember, the goal of A/B testing is to get significant insights that can inform your future marketing efforts. This means that if one hypothesis is validated, it opens up opportunities for further testing, refinement, and adapting your strategies accordingly. It’s a constantly evolving “game”.

How Long to Run an A/B Test?

The duration of your A/B test depends on several factors, such as your email send frequency and the size of your test group. However, running the test long enough to achieve statistical significance is crucial. Otherwise, the results can just be due to chance.

As a rule of thumb, running an A/B test for at least two weeks is recommended to account for variances in behavior based on the day of the week. Some A/B testing tools provide a built-in automation feature to calculate the test’s statistical significance. So the longer you can afford to run the test and gather data, the better it is, as it allows for more accurate and reliable calculations from a larger sample size.

Email A/B Testing Tools

When choosing a testing tool, consider its usability, features, and the metrics it offers for analysis. Also, check if the tool provides multivariate testing – a more advanced form where you can test multiple variables simultaneously. In no specific sequence, here is a brief overview of the top five email marketing tools with A/B Testing in 2023.

1. ActiveCampaign – a widely respected platform that offers A/B testing to customize sender details, subject lines, and content design for up to five variable versions.

ActiveCampaign email marketing

While it does not currently support A/B testing for time or audience segmentation, it makes up for this with extensive automation and marketing integration features. It’s particularly suitable for serving distinct customer groups.

2. Benchmark – tailored for small to medium-sized businesses, providing a variety of potent A/B testing features, such as subject lines and campaign comparisons.

Benchmark A/B testing


It also offers extras like Google Analytics integration, sign-up form creation, and RSS email campaigns. Its unique attribute is that it allows optimal email delivery time determination. However, a subscription is needed to access A/B testing features.

3. Get Response – this is a fast-growing platform with A/B testing tools that enable the creation of diverse styles or messages for visual and text content.

GetResponse A/B testing


It also supports subject line testing and personalizing emails via the “From” field. The platform allows strategic email scheduling based on optimal times and list segmentation for targeting specific contact groups.

4. Constant Contact – is known for its simplified approach to A/B testing, focusing mainly on subject-line testing of two variants. It suggests a minimum of 1,000 subscribers per list for reliable results.

Constant Contact homepage

Despite its limited A/B testing scope, it compensates with features like a drag-and-drop builder, in-depth analytics, and live training, making it ideal for individuals or small businesses seeking straightforward A/B testing.

5. MailChimp – a globally trusted email marketing service, offers comprehensive A/B testing features. These include customization of subject lines, professional naming in the “From” field, and subscriber list segmentation. 

Mailchimp homepage

Users can schedule emails at various times and test different components within the email content. This range of features makes MailChimp optimal for boosting open rates and conversions.

Wrapping Up

In conclusion, A/B testing is an indispensable tool for email marketing, providing invaluable insights that can help optimize your email campaigns for better performance. By consistently testing different elements, learning from the A/B test results, and implementing the winning versions, you can significantly enhance your email marketing efforts, resulting in higher open rates, click-through rates, and conversions.

In the digital age where data reigns supreme, taking a data-driven approach through A/B testing in your email marketing strategy can lead to sustained growth and success for your business.

Article by Denys Kontorskyy Technical Content Writer @Mailtrap

I am an experienced Technical Content Writer specializing in email infrastructure, offering insights on sending, testing, and optimizing emails. I also have a strong interest in product marketing, creating engaging content that drives audience engagement and supports business growth. With a focus on delivering effective campaigns and staying updated with industry trends, I bring a strategic approach to my writing that aims to achieve measurable results.