Send Smarter Emails with Easy A/B Testing
Test subject lines, content, and send times to discover what your audience loves — then automate the winner.
Email A/B testing (also called email split testing) lets you send two variations of a campaign to small segments and see which performs better. Instead of guessing, you can base your decisions on real data, improving open rates, click-throughs, and conversions. Emailer makes it simple to set up A/B tests without complex tools.
Email metrics calculator
Enter your numbers to get rates and compare them to benchmarks.
Simple Setup
Create an A/B test in minutes with no coding. Pick the element to test, set the split percentage, and launch — Emailer handles the randomization and sending.
Real-Time Results
Monitor opens, clicks, and conversions for each variant side-by-side on a clean dashboard. Know which version is winning at any moment.
Automatic Winner
Choose to let Emailer automatically send the winning variant to the remaining audience once statistical significance is reached — no manual intervention needed.
What is email A/B testing?
Email A/B testing, also known as split testing, involves sending two versions of an email (a control and a variant) to a small portion of your audience to determine which one achieves a specific goal more effectively. The goal could be a higher open rate, more clicks, or direct conversions. The variant that performs best is then sent to the remaining subscribers.
This method relies on statistical significance to ensure that the results are not due to random chance. By testing systematically, you can continuously improve your email marketing performance.
How to set up an A/B test in Emailer
First, choose the element you want to test — for example, the subject line. Create two versions of your campaign in Emailer's campaign builder. Then, specify the percentage of your audience to include in the test (typically 10-20% per variant).
Launch the test. Emailer will split the test group into two random segments and send each variant. Once the test period ends (you can set a duration or wait for a minimum number of opens), Emailer automatically identifies the winner and sends it to the remainder of your list. You can also review the results in real time.
What elements can you test?
You can test almost any single element of your email: subject lines, preview text, email body content, call-to-action buttons (text, color, placement), images, personalization tokens, and send times. The key is to test only one element at a time to know exactly what caused the difference.
For example, you might test two subject lines to see which gets more opens, or two different email layouts to compare click-through rates. After you identify a winning subject line, you could then test that same subject line with two different send times.
Best practices for meaningful results
Always test one variable at a time. If you change both the subject line and the CTA, you won't know which change drove the lift. Ensure your test group is large enough to reach statistical significance — a sample of at least 1,000 subscribers per variant is a good start for most campaigns.
Set a clear primary metric before you begin (e.g., open rate or click-through rate). Let the test run to completion rather than peeking early. Use Emailer's automatic winner feature to avoid biased decisions. Finally, document your learnings and apply them to future campaigns.
Optimize Subject Lines
Run an A/B test on two subject lines — one with a question, one with a benefit — to see which drives a higher open rate. Apply the winning formula to future campaigns.
Improve Call-to-Action Performance
Test different CTA button text ('Shop Now' vs 'Get Your Deal') or colors to increase click-through rates and conversions on your promotional emails.
Find Best Send Time
Send the same email to two segments at different times (e.g., 10 AM vs 2 PM) and see which time yields higher engagement. Emailer's A/B testing makes it easy.
FAQ
What is email A/B testing?
Email A/B testing (split testing) is a method where you send two versions of an email to a small sample of your list to see which one performs better on a specific metric, like open rate or clicks. The winner is then sent to the rest of your subscribers.
How long should I run an A/B test?
Run the test until you reach statistical significance, which depends on your sample size. For most lists, 24-48 hours is sufficient. Avoid ending early based on a small number of opens — let the test reach a reliable conclusion.
Can I test more than two versions?
Emailer supports testing two variants at a time (control vs variant). Testing more than two simultaneously reduces statistical reliability. You can run successive A/B tests to compare multiple options.
What's a good sample size for A/B testing?
Aim for at least 1,000 subscribers per variant for most campaigns. For smaller lists, you can still run tests but the results may be less reliable. Emailer's algorithm accounts for sample size when determining significance.
How does Emailer decide the winner?
Emailer uses statistical significance (often set at 95% confidence) to determine the winner. Once the test reaches that threshold, the winning variant is automatically sent to the remaining audience. You can also choose to review manually.
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