If your email marketing isn’t rooted in data, it’s likely underperforming. Many businesses send emails and hope for the best. But high-growth companies rely on A/B testing to continuously refine their campaigns and drive results. It’s the difference between guessing and knowing. In marketing that distinction shows up in your bottom line.
This article will walk you through the fundamentals of email A/B testing, what to test, how to run an effective experiment, and how to use your findings to improve results not just in email, but across your entire marketing funnel.
Why A/B Testing Matters
According to Entrepreneur Magazine, businesses that consistently run A/B tests on their emails see up to 37% higher conversion rates than those who don’t. Why? Because A/B testing removes emotion and ego from the process. It replaces assumptions with data.
If you’re scaling, you need to know what’s working and not just assume.
What You Should Be Testing
Many businesses only test subject lines. That’s a start, but it’s not enough. Pro marketers test every layer of the email experience. Here’s what to look at:
- Subject Lines – Try urgency versus curiosity, short versus long, emojis versus none.
- Preheader Text – Often overlooked but can boost open rates when done right.
- Send Times and Days – Find out if your audience prefers 8 a.m. or 3 p.m., Tuesday or Sunday.
- Email Body Copy – Compare short-form with long-form, or storytelling with direct messaging.
- CTA Buttons – Test placement, color, wording, and size to boost click-throughs.
- Images vs No Images – Some audiences respond better to plain-text emails.
As Fast Company notes, small changes can lead to big results. You just need to know which elements drive behavior.
How to Set Up a Smart A/B Test
Running a successful A/B test doesn’t have to be complicated. Just follow these fundamentals:
- Test one variable at a time. If you change five things, you won’t know which one made the difference.
- Split your audience evenly. Most email platforms will do this automatically.
- Use a large enough sample size. Avoid drawing conclusions from just 20 opens. Aim for a few hundred per variation.
- Let it run long enough. Depending on your audience size, allow 24-72 hours before declaring a winner.
Consistency matters. The goal is to test regularly, not just occasionally.
What to Do After the Test Ends
Once your test has finished, here’s how to turn insights into action:
- Review multiple metrics. Don’t focus only on open rate. Look at clicks and conversions too.
- Apply your learnings. Update future campaigns using the winning elements.
- Document results. Build a library of what works so your team can iterate faster.
Business Insider reports that top-performing brands treat testing as a repeatable system, not a one-off experiment.
Pro Tip: Extend Learnings Beyond Email
What you learn from email A/B testing can help improve your overall marketing strategy. Here’s how:
- Use high-performing subject lines as headlines in ads.
- Repurpose successful CTAs across your website and landing pages.
- Turn your most engaging email content into blog snippets or social media posts.
A/B testing isn’t just a tactic. It’s a lens into what truly moves your audience to act.
Frequently Asked Questions About Email A/B Testing
What’s the biggest mistake to avoid when A/B testing emails?
Testing too many variables at once. Focus on isolating one change per test.
How long should an email A/B test run?
Typically 24 to 72 hours, depending on your audience size and send volume.
What tools should I use for email testing?
Platforms like Mailchimp, ActiveCampaign, and Klaviyo all offer built-in A/B testing features.
Can A/B testing hurt performance if done wrong?
Yes. Poor test design or incorrect data interpretation can lead to bad decisions. Follow best practices and keep a testing log.
Should I test every email I send?
Not necessarily, but you should test often enough to build a data-backed strategy.
Conclusion: Stop Guessing and Start Optimizing
In high-growth marketing, you can’t afford to make decisions based on assumptions. Testing leads to clarity. Clarity leads to revenue.
Ready to build smarter campaigns using data instead of guesswork? Book a free discovery call and let’s start optimizing your strategy.
Citations
- Entrepreneur Magazine – Why A/B Testing Is a Must-Have in Digital Marketing
- Fast Company – Small Changes, Big Gains: The Power of Micro-Testing in Email Marketing
- Business Insider – How Top Brands Use Email Testing to Drive Conversion