email marketing running ab tests

Email Marketing: Why Should You Conduct A/B Tests?

Posted on By Simon Gorlak
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Email Marketing: Why Should You Conduct A/B Tests?

I’m guessing this is one of the most common questions you’ve heard. And as you might expect—there are plenty of answers.

On one hand, you run an A/B test to figure out how to boost your conversion rate. On the other, someone might just ask you to do it for them. Either way, you’re working towards the same goal.

That’s why I thought of writing about why it’s so important.

Alright, the importance is obvious, but you’ll also learn:

  • what to A/B test
  • how to run A/B tests
  • when you can finally say: well done, I’ve found the answer!

And a few other things.

Enjoy the read!

What Is A/B Testing in Email Marketing?

I assume that if you’re reading this post, you’ve already come across more than one definition of A/B testing. Let me simplify it as much as possible:

A/B testing in email marketing is the process of testing selected elements with the goal of maximizing conversions. The results will help tailor those elements to your campaigns, making them as profitable as possible. Period.

(P.S. That’s only my definition, not somebody’s from the internet).

Consistently conducting tests often yields the best results. Of course, you shouldn’t run them too frequently or just once in a while. The optimal timing is once every three weeks (though it also depends on the industry) to determine which elements work best.

Here are the most common 11 elements in email marketing that you can test:

  • CTAs
  • Email Body
  • Send Times
  • Email Length
  • Subject Lines
  • Segmentation
  • Personalization
  • Links & Navigation
  • Images and Visuals
  • Testimonials (adding every time or not)
  • Subject Line Emojis (more or less emotional)

The A/B testing process is a highly effective way to understand which elements of your email resonate with your audience, as you can directly see what is working and what isn’t. The beauty of A/B testing lies in its versatility—you can test almost any element (as I’ve shown above) of your email campaign.

Why Is A/B Testing Important?

Without testing, you’re literally guessing what will work best for your audience. A/B testing provides specific data on the performance of different elements within your email, giving you actionable insights that can improve your results.

Of course, when conducting A/B testing, you aim to improve specific metrics of your email marketing performance. Here are the four most important ones:

  • Increasing conversion rates: By testing different call-to-action (CTA) buttons, you can figure out which drives more conversions. Perhaps the more straightforward, or the second less intrusive, would resonate best with your audience.
  • Improving open rates: Tweaking elements like subject lines leads to higher open rates.
  • Boosting response rates: Hell yeah, everybody wants to hear back from our prospects. Personalizing content and testing different tones opens the door to a more engaged audience.
  • Reducing unsubscribe rates: Last, but very not least. By testing email frequency or content, you can reduce (but you can’t always take it for granted), the number of people opting out of your list.
Read also:  10 Necessary Questions for Bloggers

In a nutshell; this is why A/B testing is so much important. In that post, I’m breaking down email marketing. However, you can A/B test every component in any given industry. 

A/B Testing in Action: What Elements Can You Test?

Let’s start from scratch.

You can—and actually, you must—A/B test as many elements as possible. This will help you discover what works and what doesn’t in your particular case.

One important thing to keep in mind: Test one variable at a time.

Why?

If you test multiple variables at once, how will you know which one caused the change?

Exactly.

Give it a try, and let the A/B testing reveal the right solution.

Now, let’s move on to the key elements of email marketing that should be tested.

Email Subject Line

Messaging on LinkedIn subject line

Jokes aside—the email subject line is an essential part of your email marketing. You can craft the perfect email body, personalize it like a boss, but if your recipient doesn’t like the subject line, your email wind up in the trash.

That’s exactly why email subject lines are absolutely crucial.

I’m gonna tell you the secret sauce: the most observable mistakes are the tone of the email title & the number of characters. Let me explain.

The Tone of the Email Title

Email marketing visual effect

Marketers often treat the subject line as an afterthought, something to throw in at the end. That’s a mistake. Often, the subject line feels disconnected from the email content.

Example:

👉 Email Subject Line: “Simon, 20% discount for you!”

👉 Email Body: “Hey Simon, I wanted to ask if we could get back to our discussions? Thanks.” 

———

Hmm, did I miss something? Where’s the discount mentioned?

You see, right? This is the kind of lapse that happens when the tone of the subject line doesn’t match the email body.

👉 Pro Tip: First, write your email, then adjust the subject line. If the email body shifts, tailor the subject line to match. But the rule is constant—the tone and message must feel cohesive and well-thought-out. Otherwise, your prospect will feel like me (and you) a few sentences ago.

The Number of Characters

Prospecting on LinkedIn message

It depends. It depends on the devices. Let’s start with the most common one:

Mobile: The optimal length is around 25–30 characters. It’s not a lot, I know. You gotta be succinct and straightforward. Mobile screens have limited space, so shorter subject lines are more readable and effective.

Desktop: You can use a longer subject line, usually around 50–60 characters, though some email clients may display up to 70 characters. However, it’s still important to prioritize brevity and clarity.

Email Body

Email body example

We’ve got it—your prospect is moving on!

Once your prospect opens the email, it’s time to focus on the next element: the email body.

The email body is the art of email marketing. This is where you can let your creativity shine. But remember, the prospect is still just that—a prospect. You’ve got something to sell, so your first priority is to show your value. 👈

Read also:  9 Best Ways to Personalize Email Subject Lines

That’s why your email body shouldn’t be too long or too brief. The ideal length is between 500–650 characters. This is the sweet spot for cold emails and cold messages (like those on LinkedIn).

Of course, it can vary depending on the message, whether you’ve spoken with the decision-maker before, and other factors. But generally, the more concise the message, the better the outcome.

Personalization

Apollo.io email personalization
Image source: Apollo.io

Alright, your email is almost ready, but there’s one more piece of the puzzle: personalization.

Who doesn’t like to get the personalized message, right?

Why is it so important? Simple—nobody wants to feel like they’re just another name on a list. Personalization helps you stand out and makes your prospect feel like you’ve taken the time to understand them.

A personalized email goes beyond just adding their first name. It’s about showing you know their pain points, their goals, and how your solution can help them succeed.

But don’t exaggerate! The key is to balance personalization with brevity. Mention something specific to their company or industry, and show them you’ve done your homework. A tailored message has a higher chance of getting a response than a generic one.

Keep in mind: Personalization isn’t just a tactic—it’s a strategy for building trust and credibility.

Takeaway? Personalize your email in a way that feels genuine, but keep it focused. The more relevant your message, the better your chances of moving the conversation forward.

Let your prospect know you’re speaking to them, not at them.

Email Length

Email F pattern

Again—let’s talk numbers.

We’ve all been there—opening an email only to be overwhelmed by a wall of text. 😩 So, how long should your email actually be?

The truth is, there’s no one-size-fits-all answer. However, when it comes to cold emails or initial outreach, keeping it short and to the point is key. Think of your email as a conversation starter, not the whole discussion.

An ideal length? Aim for 50 to 125 words. That’s around 500-650 characters—just enough to get your point across without losing your prospect’s attention. Remember, people are busy, and no one has time for a long-winded pitch.

Your email should incorporate three basic things:

👉 Spark curiosity – Make them want to know more.

👉 Get to the point – Highlight the value you bring early on.

👉 Include a clear call to action – What’s the next step that should be taken?

If you’ve already spoken to the prospect or built some rapport, you can go a little longer. But for first impressions, being short and impactful wins the game.

So, trim the fluff, keep it focused, and always ask yourself: “Would I want to read this if I were in their shoes?”

Remember—brevity is your best friend in email marketing.

Call-to-Action (CTA) Button

So, you’ve come up with the perfect email—now what? It’s time to guide your prospect toward the next step, and that’s where the Call-to-Action (CTA) button comes into play. 🟢

Read also:  7 Steps to Building an Effective Content Strategy

A great CTA is like a bridge between curiosity and conversion. It needs to be clear, compelling, and impossible to ignore. But what makes a CTA button effective?

While you’re writing the CTA, don’t forget about these 4 elements:

  1. Be Direct: Don’t leave them guessing. Use action-oriented words like “Get Started,” “Download Now,” or “Schedule a Call.” Your prospect should immediately know what they’ll get by clicking.
  2. Keep It Simple: One email, one CTA. Don’t overwhelm them with options. When there’s just one clear action to take, it boosts your chances of success.
  3. Make It Stand Out: Design matters! Your CTA button should pop visually. Whether it’s bold colors, strong contrast, or strategic placement, make sure it grabs attention without being over the top.
  4. Create Urgency (FOMO): Add a little nudge by incorporating urgency or scarcity. Think “Limited Time Offer” or “Only a Few Spots Left.” It encourages faster decision-making.

Your CTA is the gateway to conversion. It’s not just a button; it’s the next step in the customer journey. The goal? Make it irresistible to click!

Keep it actionable, keep it focused, and guide your prospect to take that next step with confidence (literally!).

Takeaways

What can you actually A/B test in email marketing?

The most common elements are:

  • Email body
  • Email length
  • Personalization
  • Email subject line
  • Call-to-action (CTA) buttons

And a few more, but you already know which ones.

Main goals:

  1. Increasing conversion
  2. Getting a higher open rate
  3. Getting a higher response rate

>> Take into account that you can test many more elements [e.g., email frequency (sending 1/week or more)] to find out more goals (e.g., reducing the unsubscribe rate).

If you want to know what works, and what doesn’t—implement A/B testing.

Pro Tip: Always A/B test only one element at a time (e.g., email subject line). 

Why?

If you test multiple elements simultaneously (e.g., email subject line, email body, and links), how will you know what actually caused the change (e.g., higher response rate)?

The rule is simple: 1 A/B test = 1 element to be tested.

How do you run your A/B tests? Maybe you’ve got some ideas that I haven’t covered?

If so, hit me up, I’d be glad to overwrite some gaps!

P.S. If you’ve enjoyed this post, don’t forget to drink a coffee with me! 😉

Drink a Coffee Together! ☕


Thank you for contributing,
Simon

Author Profile

Simon Gorlak
Simon Gorlak is a Digital Marketing Expert with over 8 years of experience. He specializes in 3 areas: SEO, Copywriting, and Email Marketing. Simon's blog gathers knowledge that helps Marketers & C-level to increase profits from their online businesses. Also, his content helps to reach the most difficult customers, make others' content to be read & purchased. Besides digital marketing, Simon speaks 4 languages: English, Spanish, Portuguese, and Polish & works as a Head of Business at an Indian Start-up.
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Email Marketing, Performance Marketing