One of the keys to success with email marketing is constantly testing to see what works and how you can improve your email campaigns. 

While you might be tempted, like many email marketers are, to just rely on your gut feeling, the problem with relying on your assumptions or guesses is you’re not always going to be right. 

There are going to be times when your email list reacts more positively toward something, be it a design, subject line, call-to-action, etc. over a variant you could’ve sworn they’d prefer. That’s why it’s important to regularly run A/B tests so that you know you’re making evidence-based decisions that are actually improving the performance of your campaigns. 

If you haven’t performed any A/B tests before, you might unsure of what it involves, what the benefits to them are, and even what you should test. The good news is that A/B testing is an incredibly simple form of testing. 

Defined: A/B Testing for Email Marketing

A/B testing, also known as split testing, is incredibly simple in that all it involves is sending two different variants (an A variant and a B variant) to your email list and seeing which variant performs better. 

The difference between variants could be something small like a differently worded subject line that most subscribers aren’t going to notice. Or it could be something more substantial like an entirely different email design and layout. 

Good A/B testing will, however, only test one element at a time. That way you can be more confident that any difference in how the two variants performed is down to that one element. As opposed to trying to determine which of the elements resulted in the change (and relying on gut feelings again). 

In terms of measuring performance, there are several potential email metrics you should be looking at:

  • Open rates (the number of people who open and read your email)
  • Click rates (the number of people who click on a link within your email)
  • Conversion rates (the number of people opening your email who go on to make a purchase)

Benefits of A/B Email Testing

By running regular A/B tests, you’ll gradually start improving your key email marketing metrics. Which are:

1. Improved open rates.

By testing the factors that influence your open rate (e.g., your subject lines and preview text, etc.) you’ll get a better idea of what resonates with your subscribers and what doesn’t. This will allow you to optimize your future campaigns for more opens.  

2. Improved click rates.

Just like with your open rates, by testing elements within your email you’ll slowly but surely get a better understanding of what type of content and links your subscribers tend to click on. You can then create your future emails around what you know works to improve your click rate.

3. Improved conversion rates and sales.

By improving your open and click rates, you’ll be driving more potential customers to your site. This will ultimately result in more sales, and (especially if you also A/B test elements on your store) will also result in an improved conversion rate. 

What Can You A/B Test?

While there are a few things that immediately spring to mind in terms of what to A/B test, when it comes to email marketing, there are many potential tests that you can be running. These include:

1. Your subject lines.

Subject lines are one of the most popular elements of campaigns to test for email marketers. Part of this is because they’re easy to change and most marketers often already have a couple of ideas for potential subject lines. 

Once you know what the two subject lines you want to test are and you’ve sent the email, the metric you’ll want to keep an eye on is your open rate. 

While it’s worth also paying attention to your click and conversion rate, your subject line is one of the few elements of your campaign that subscribers will see before they open your email. That’s why the metric that’s going to be impacted the most from experimenting with your subject line is going to be your open rate. 

After your email has been opened, the email design and its contents are going to have a much greater impact on whether people click through to your site and then make a purchase or not. 

2. Your preview text.

Your preview text is the optional additional line of text that proceeds your subject line. This means it performs much the same job as your subject line and is also a great candidate for A/B testing. 

Just like when testing different variants of your subject lines, the main metric you’ll want to track when experimenting with your preview text is your open rate. 

3. The sender name.

Your sender name is the name your subscribers see in their inbox of who sent the email.

For most brands, this is usually just their brand name. For example, “ACME Brand”. Some brands, however, will add a bit of personality to their sender name by including the name of someone like their founder. For example, “Jane from ACME Brand.” 

This might be something worth experimenting with some of your future email campaigns. If you decide to run this type of A/B test, the metric to pay attention to is your open rate.

4. When you send your emails.

It’s common for email marketers to fall into a habit of always sending their campaigns at the same time of day and the same day of the week. However, when you send your emails can have a major impact on your open rate. 

To really know when the best day to send emails to your customers is, you should run some A/B tests where you vary the day of the week (e.g., Tuesday vs. Thursday). You can also do the same with the time of day (morning vs. afternoon). 

Again, the main metric you’ll want to look at here is your open rate.

5. Your call-to-action text.

Call-to-actions (also known as CTAs) are an incredibly important part of your email. It’s the part of your email that gets your subscribers to perform the action you want them to (e.g., click through to view a certain product collection or redeem an offer). 

Given how important it is, it’s well worth testing different variants of your CTA wording. For example, “Grab Yours Before Stocks Run Out” vs. “Hurry! Buy Now to Avoid Disappointment”. 

Because CTAs are usually directing people to click through to a particular page, the metric they’ll influence the most is your click rate. 

6. Which landing pages you funnel people to.

Speaking of CTAs, it’s also worth testing which pages they direct your subscribers to. For instance, instead of linking to a product collection, it might be better to link to a dedicated landing page for your current sale. 

As your subscribers usually don’t know exactly which page they’ll end up on until after they’ve clicked on the link, the metric you’d be looking at here is your conversion rate. 

7. The length of your emails.

Some merchants tend to prefer to send long emails that showcase plenty of their products. Others opt for shorter emails that are to-the-point. 

In either case, you might want to experiment with how your subscribers respond when you send an email that’s longer or shorter than what you’d usually send and seeing what effect it has on your click rate.

8. Your email design.

There are many factors that go into your email design such as the layout, how many columns you use, the style of images, whether you use images at all, etc. 

While you shouldn’t play around with too many different elements during the one A/B test, otherwise you won’t be sure which change led to the results, it’s worth experimenting with your email design. 

9. How you great your subscriber.

While you should always be personalizing your emails with your subscriber’s name, there is room to experiment with how you great them. For instance, “Hey Darcy” vs. “How’s it going, Darcy?”. 

This is something that’s quick and easy to change between your two variants but may have an impact on how your subscribers engage with your campaigns. If a particular style of greeting resonates with your subscribers more, then you’d expect your click rates to go up. 

10. Trying out new ideas.

If you’ve had ideas for potential things you could add to future emails but aren’t sure how your subscribers will react, then an A/B test is the perfect way to find out. 

For example, if you’re thinking about including customer testimonials as a form of social proof, you can include them in only one of the variants and see whether they improve your click and conversion rates. 


A/B testing is a simple yet powerful way to improve your email campaigns. 

All it involves is creating two variants of the same email and seeing which one resonates with your subscribers more. 

By doing this regularly, you’ll constantly be refining and optimizing your campaigns, maximizing your open, click-through, and conversion rates in the process. 

With many email apps letting you set up these tests quickly and easily, there’s no reason not to be constantly A/B testing!

BigCommerce helps growing businesses, enterprise brands, and everything in-between sell more online.

Start your free trial
High-volume or established business? Request a demo

Start growing your ecommerce business even faster.

Start Your Free Trial

High-volume or established business? Request a demo