Ilma from MailerLite

Ilma7 min readTips and resourcesSeptember 14, 2016

Email A/B split testing: 6 ideas to start with

Email A/B split testing: 6 ideas to start with

Before you start A/B testing your email campaigns, there is one rule to remember – always make sure you’re testing only one element at a time. Otherwise you will not know what change was responsible for the shift in conversions.

You can A/B test different things in your newsletters – from the subject line to the colour of a call-to-action button. Each of those things is likely to have an effect on different parts of the conversion process.

1. Test subject line

email a/b split testing subject line

There are many ways you can A/B test your subject line. Let’s take a look at some of them.

  • Ask a question in your subject line. Most tests show that asking questions can have a very positive effect on open rates. Questions are not meant to be left unanswered. Using a question will inspire readers to open your email in search of that answer. Subject lines beginning with ‘Did you know…’ and ‘Do you want…’ are great ways to catch your readers’ attention and keep them reading. Try it with your audience. Rather than writing: 3 ways to boost your productivity, you might say: Do you want to boost your productivity?
  • Personalize. Using your reader’s name or location in the subject line adds a feeling of connection, especially when it’s a name. Everyone loves the sound of their own name. Plus, it increases clickthrough rate. Just don’t overuse it. Rather than writing: 20% off sale! you could write: Janet, we’re giving you 20% off this week
  • Use symbols or numbers. Using non-standard characters like ☞ or numbers in the subject line is an easy way to stop your reader's wandering eye and catch their attention. You can also try using emojis.
  • Create a sense of urgency. Fear of loss is a stronger motivator than the desire to gain. We all hate losing. Position your offer so that it feels like a loss to your audience if they don’t get it. Subject lines that create a sense of urgency and exclusivity can produce 22% higher open rates. Use phrases like “don’t miss out”, “today only” or “24-hour giveaway” in your subject lines – it will encourage your readers to act now instead of putting it off until later.

2. Test the sender’s name

email a/b split testing senders name

I believe that the ‘from’ field is even more important than your subject line. You don’t care what the subject line of the email is if you received from your mum, right? That’s the point. We usually open and read emails that are sent by someone we trust and know.

  • A real person versus company name. If you’re working in a company, experiment with your company name vs. the name of your marketing person vs. the name of your CEO/founder. Usually, when senders include their own name (and also a company name), those emails have higher open rates. Rather than saying the email is from MailerLite, you might write Ilma from MailerLite
  • Your full name vs. your first nameSeth Godin gets higher open rates using ‘Seth Godin’ as opposed to just ‘Seth’.
  • Different email addressesIf you’re sending emails from info at you may want to test this against personal email at
  • Male vs. femaleDepending on your audience, you may want to experiment with having a male versus a female sender.

3. Email content

email a/b split testing call to action (CTA)

A call-to-action or CTA is the most important part of every email. It’s the final gateway before a reader converts.

  • Repeated CTAs. Including too many links is overwhelming – but having just two or even three links pointing to the same ultimate goal generally leads to a lift in conversions rather than a drop-off. CTAs are usually best placed on a clickable button. Try to repeat your CTA in your signature or postscript (P.S.) – you’ll be surprised by the results.
  • Text on buttons. Try shorter and longer text versions. Try usual CTA versus creative. Play around with text to see which word or phrase converts more visitors. Rather than writing: Buy Now/Purchase/Add to Cart…try writing: I’m in! Let’s do this!
  • Test different sizes, fonts and even ALL CAPS (For some reason this perform the best. See if it works for you.)
  • Different colours for buttons. Use contrasting colours. Some marketers say that the colour red increases click-through rate.
  • Try varying the location of your CTA button, making some CTAs more prominent than others.
  • Consider using arrows and other visual elements to guide the reader → Some of the most successful CTAs out there have arrows pointing at them. It creates a sense of direction and guides the visitor to the important element on the page. This is a way of prioritizing information and creating a flow. Test it.

4. Test images (or no images)

email a/b split testing images (or no images)

Image is a powerful tool to convince your customers to act. Experimenting with images is a fun way to get the pulse of your readers to see what types of images they respond to and how your images can drive the engagement. Here are some ideas of what you can test:

  • Image of people versus a product is a good place to start.
  • One versus multiple images.
  • Text on image versus no text.
  • Screenshot of a video.
  • Animated GIF versus static image.
  • Serious straightforward image against a goofy one.
  • Colorful visuals versus black and white visuals.
  • A stock image stacks versus an image of your employees or customers in action.

5. Test the layout

email a/b split testing layout

You may also try to test different layouts of your emails. It is important that you find the best one which is conducive to engaging with your readers.

For example, you can test a single column versus multiple columns, one paragraph versus two, or different placements for different elements.

6. Test the preheader text

email a/b split testing preheader text

When customers receive your email, the subject and preheader text will be the key elements they will use to determine if opening and interacting with your email is worth their time.

Preheader text is like a continuation of a subject line so you can test it in the same ways as a subject line: ask a question, create a sense of urgency, etc.

And one more thing…

A/B testing is never done. There is no end to what can be tested and what knowledge can be gleaned from testing. If something works well in a few A/B split tests – keep doing it, and move on to test another aspect of your email. Also remember, what works today will not necessarily work tomorrow.

Ready to have fun? Start A/B testing today to improve your email conversions tomorrow.

Editor’s note: This post was originally published in August, 2015 but has been updated for accuracy and comprehensiveness.

Ilma Nausedaite

Hi, I’m Ilma, CMO at MailerLite. I love seeing our customers succeed. When they win, we win (like being named one of the top 5 fastest growing SaaS companies). Email is my passion, although I took a rather unusual path. Before MailerLite, I worked in finance and art, which turned out to be the perfect mix for marketing.