A/B Testing Ideas for Your Next Email Marketing Campaign

A/B testing (also known as split testing) is one of the most effective ways to improve the performance of your email marketing. By testing two variations of an email with a segment of your audience, you can make data-led decisions about what works best, and what doesn’t work at all, and apply those insights to future campaigns.

But what exactly should you be testing? Here are some simple yet powerful A/B testing ideas, as well as some guidelines for using them, to help you optimise your next email send.

1. Subject Lines

The subject line is your first, and sometimes only, chance to grab attention. Test short vs. long subject lines, different tones (casual vs. formal), or specific elements like emojis, numbers, or questions. You can also test sending it out with the recipient’s name in the subject line, vs a generic subject.

Small changes can have a big impact on open rates.

• A: “Don’t Miss Out – Half Price Sale Ends Tonight”
• B: “Last Chance to Save – 50% Off Ends at Midnight 🕛”

2. Send Times and Days

Timing is another important test for email marketing campaigns. Time of day is a huge factor in email marketing. 

Test different days of the week or times of day to see when your audience is most likely to open and click. What works for one industry or audience may not work for another, so don’t try to apply a blanket rule to everyone.

3. Call-to-Action (CTA) Buttons

Your CTA is what drives clicks, so it’s worth testing.

You can experiment with wording (“Shop Now” vs. “See the Collection”), colour, size, or even placement within the email. Clear and compelling CTAs typically perform best, but it’s worth seeing what resonates with your audience.

4. Personalisation vs. No Personalisation

Personalised emails often perform better, but it’s not always a guarantee. Try testing a personalised greeting (“Hi Sarah”) or subject line against a more generic version. You may find that in some contexts, simplicity wins.

5. Layout and Design

Does a single-column layout perform better than a more visual, multi-section design? Do large product images drive more engagement, or do people prefer brief, text-based emails? Try testing one design element at a time to pinpoint what works.

6. Content Focus

If your email includes multiple messages, a sale, a blog post, and a product launch, try testing a simplified version that focuses on just one message. Too much information can dilute your CTA, and A/B testing can show you which content mix drives the best results.

Start Small, Learn Fast

The key to successful A/B testing is to isolate one element at a time, keep your sample size meaningful, and review the results with a critical eye. Over time, these small improvements can lead to significant gains in open rates, click-throughs, and conversions.

Need help improving your email marketing strategy? We can support you with data-led campaigns that deliver measurable results.