Benefits of performing an email A/B test
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Email marketing is still one of the most effective ways to reach new and existing customers online. Add the ability to optimize those campaigns with email A/B testing through your email marketing tool, and you have everything you need to improve engagement and increase revenue.
Email A/B testing helps optimize engagement by comparing variations (like subject lines, CTAs, or visuals) to see which version performs best with your audience.
Running effective tests requires clear goals, random audience segmentation, and statistically meaningful sample sizes—typically at least 1,000 recipients per version.
Small changes can drive big results, so marketers should continually test, analyze, and refine emails to boost open rates, clicks, and conversions.
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Although A/B testing is incredibly powerful in email marketing when executed correctly, marketers often overlook it. We’re here to show you how effective an email A/B test can be and how to plan and deploy yours.
A/B testing in email marketing involves sending variations of an email campaign to a segment of your subscriber list. A portion of that segment receives variation A, and the other portion receives variation B.
These versions can differ in one small element, or the two could be entirely different emails. Deciding on what to test and how to test it will come down to your business, audience, and campaign objectives. But we’ll go into more of that later.
The point is to determine which version returns the best results in terms of open and click-through rates. You’ll send this winning variation to the remainder of your subscriber list, knowing it’s more likely to improve audience engagement.
Using an email marketing tool like Nutshell’s email marketing makes A/B testing easier. An email marketing tool gives you access to features that let you seamlessly create email variations, manage your subscriber subsets, and automate your tests.
Some of the most significant benefits you’ll experience when carrying out email A/B testing include:
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Nutshell’s email marketing software plugs directly into your CRM data, so you can create highly targeted audience segments, track the impact of your emails in real-time, and manage all your communications out of a single tool. Get started for free!
Setting up an email campaign A/B test can sound intimidating, but it’s easier than you might expect. Using quality email marketing software will give you access to all the tools you need to set up an effective test.
While several good apps exist, Nutshell offers a robust email marketing tool that includes user-friendly A/B testing features and connects directly to your CRM, letting you manage contacts and communication with them from one convenient interface.
With Nutshell’s email marketing, you can create broadcast and newsletter email campaigns with A/B testing in no time by following these easy steps:
You can test almost any aspect of your email to see what best resonates with your audience. That said, here are a few of the most common and impactful email elements marketers test with A/B testing.
We’ll begin with your email subject line, as it’s the most prominent part of your email as viewed in your subscriber’s inbox. It’s the first thing your subscriber reads and dictates whether they’ll open your email.
You can change various aspects of your subject line to do an A/B test, including its length, word order, content, and personalization.
Tweaking your subject line to increase or reduce its length may make it easier to read or more attention-grabbing, resulting in more opens. Aim for a subject line under 70 characters to ensure it fits in the space provided. 50 to 70 characters is typical for effective campaigns.
Creating an email variation with your subject line wording in a different order may reveal specific phrasing that resonates more with your audience. And if your email contains more than one piece of content, it may be worth highlighting different topics in version A and version B’s subject lines.
Another option is adding your subscriber’s name to the subject line for a personal touch. Many big brands do this with their email newsletters because it can be very effective for increasing opens.
Depending on your subscriber’s email client and device, they’ll likely see a message preview snippet just after the subject line. Usually, this shows the first line of the email, but you can adjust this to display something specific.
One option is to create a short summary of what your email is about. Another is to turn your message preheader into an action-oriented statement, compelling the subscriber to open the email.
Your email subscribers may use preview text to determine what to expect from your email. Because of this, although preview text may not get as much attention as subject lines, it’s another valuable option for increasing open rates.
It’s widely known that people often find visual elements easier to process than paragraphs of text. That’s why online marketing assets, from websites to ads, social media posts, and blog posts, include some form of imagery.
The same applies to high-converting email newsletters and broadcasts. Visuals are a great way to gain the reader’s attention, convey your core message, and encourage the audience to read the text.
These visual elements can include illustrations, creative backgrounds, branding, screenshots, and photos. But, imagery is not always necessary and could even become a distraction in some situations.
Using A/B testing in your email marketing offers a way to determine whether email visuals make a difference to your click-through rates. You can send a test email with images and another without, or two with the same imagery but in different colors.
You could also test different layouts and visual styles to see how your subscribers respond. Doubling down on the visuals that work best during your A/B testing could increase campaign clicks and conversions.
Email marketing calls for messages that get to the point quickly and that readers can easily understand. Testing your email content to see which version gets you more clicks is a great way to find out if readers respond to your message and take action.
Due to the way we receive information today online and via social media, the average attention span is declining. For this reason, short, punchy messages often perform the best.
That’s why testing the length of your email content is one of the most popular A/B tests. You could create a version that communicates the bare essentials in text and incorporates striking visuals and another with more text that describes the product’s features and benefits.
The version that delivers the highest click-through rate is your winning variation. Of course, the success of your longer or shorter email newsletter will depend on the complexity of your product, your industry, and your audience.
Another content test element relates to personalizing your message. Personalization can often make your content feel more relevant to the reader. But it may not be effective in every instance.
Create an A/B test email variation with personalized information, like the subscriber’s name, company name, or location. Using an A/B testing tool that integrates with your CRM will make personalization much easier since the tool can pull contacts’ information right from your CRM.
An integral part of encouraging your subscribers to click and take action is the CTA itself. How your CTA looks, whether it’s easy to find, and what it asks your readers to do all play a role in the success of your email campaign.
Not sure whether you should include buttons or hyperlinks as your CTAs? Create an email A/B test to see which grabs your subscribers’ attention and results in more clicks.
Sometimes, a simple “Find Out More” CTA anchor or button text is enough. However, being more specific and action-oriented with your CTA message is often beneficial. For example, you could create an email variation with CTA text that explicitly asks your reader to act, like “Download Your Free Copy Now!”
You could also play around with CTA placement and colors to determine which version catches your audience’s eye. Again, different approaches work for different audiences and businesses, so test it out to see how your subscribers respond.
Now that you know how A/B testing in email marketing works and what elements you can test, let’s break down some key factors to consider before launching your campaign, such as:
At Nutshell, we’re passionate about helping your business grow. One of the ways we do that is by offering top-notch marketing tools that work hand-in-hand with your CRM to build relationships with prospects and existing customers.
Our Email marketing add-on is more than your average email marketing tool. With it, you can easily craft attention-grabbing emails, enhance audience targeting, and measure campaign performance through various metrics.
Nutshell’s email marketing also lets you build impactful email A/B testing campaigns to help you learn more about your audience and improve open and click-through rates.
Test broadcast emails or newsletters with Nutshell’s email marketing software, selecting your objective, the winning version, your test audience percentage, and how long you’d like to run your test.
You can use our robust, easy-to-use email design features and top-quality templates to create captivating A/B test emails in a flash. Benefit from a ton of data giving you insight into your audience and how they interact with your emails, and use that data to level up your campaigns.
Not sure where to start? Speak to our friendly support team, who will help you with any questions you have.
Give Nutshell’s email marketing features a try when you sign up for a free 14-day trial of Nutshell and put our email A/B testing feature to the test.
Run your test for at least 24-48 hours to capture different time zones and email-checking behaviors. For campaigns with smaller lists or lower engagement, extend to 3-7 days. Don’t stop early when you see promising results—wait for statistical significance to ensure reliable data.
Ideally, send each variation to at least 1,000 subscribers for statistically significant results. With smaller lists (under 2,000 total), you can still test by splitting 50/50, but results may be less reliable. Focus on testing high-impact elements like subject lines to maximize learning.
No. Test one variable at a time in A/B tests to clearly identify what drives results. Testing multiple elements simultaneously (multivariate testing) requires significantly more traffic and makes it harder to pinpoint what worked. Start simple, learn fast, then move to your next test.
An inconclusive test means neither version performed significantly better—often due to insufficient sample size, high variance, or genuinely similar performance. Don’t force a winner. Instead, run the test longer, try a more dramatic variation, or test a different element that might have bigger impact.
Yes! A/B testing works great for automated sequences like welcome series, drip campaigns, and nurture emails. Test one email at a time within the sequence, measuring how changes affect downstream engagement and conversions. Nutshell’s email marketing makes it easy to optimize automated workflows.
Take our guided tour to explore Nutshell’s incredible features!
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