How to A/B Test Your Small Business Email Campaigns for Better Results?

Back when I first started email marketing for my small business, I used to just hit “Send” and hope for the best.

If the open rate was decent, I celebrated. If not? I shrugged and blamed the algorithm.

Turns out, I was missing a huge opportunity: A/B testing.

Once I started testing different parts of my emails — subject lines, CTAs, even send times — I started to see real results. Higher opens, more clicks, and, most importantly, more sales.

If you’ve been sending emails without knowing what’s actually working, let me walk you through how to A/B test your small business email campaigns — without getting overwhelmed.

What Is A/B Testing in Email Marketing?

A/B testing (also called split testing) is when you send two versions of an email to a small part of your list to see which one performs better — then send the winner to the rest.

You can test things like:

Subject lines
Email copy
CTAs
Images
Layouts
Send times

The goal? Find what makes people open, click, and convert.

Step 1: Choose One Thing to Test

Here’s the golden rule of A/B testing: only test one variable at a time. If you change multiple things, you won’t know what caused the difference in performance.

Start with something simple like:

Subject line A vs. Subject line B
CTA button that says “Shop Now” vs. “Grab Your Deal”
Long email vs. short email

Pro Tip: Subject lines are usually the easiest place to start — and they often have the biggest impact.

Step 2: Decide What Metric You’re Optimizing For

Before you hit send, ask yourself: What do I want to improve?

Examples:

Open rate → test subject lines or sender name
Click-through rate → test CTAs, images, or body copy
Conversions → test offer positioning, pricing, or urgency language

Know your goal before running the test — otherwise, you’ll just be staring at random numbers.

Step 3: Segment Your List

Most email platforms (like Mailchimp, MailerLite, ConvertKit, etc.) let you do this automatically.

Here’s how it works:

You send version A to 10% of your list
Version B to another 10%
Wait a few hours
The winner (based on opens or clicks) gets sent to the remaining 80%

Set the split to at least 20–30% of your list if you want meaningful results.

Step 4: Let the Test Run Long Enough

I used to check results after 10 minutes. Big mistake.

Give your test at least 4–6 hours (preferably 24) to collect enough data — especially if you’re testing subject lines or send times.

Impatient? Set up your email tool to auto-send the winner after a set window — that way, you don’t have to babysit it.

Step 5: Analyze What Worked (and Why)

Let’s say subject line A got 18% opens and B got 12%. Great. But don’t just move on — ask why.

Was A:

Shorter?
More urgent?
More curiosity-driven?
Personal?

Take note. Apply what you learn to future emails.

Then build on it.

For example:

First test: “20% Off Ends Tonight” vs. “Last Chance to Save 20%”
Next test: Use the winning format and test emojis or personalization

A/B testing is iterative — you improve one step at a time.

What Should You Test First? (Priority List)

Subject Lines – most impact on opens
Call to Action (CTA) – big influence on clicks
Preview Text – that line under the subject line in inboxes
Email Layout – single-column vs. two-column, text-heavy vs. visual
Send Time/Day – test weekday mornings vs. weekends
Sender Name – brand name vs. personal name (“Sarah from [Brand]”)
Offers – percentage vs. dollar discounts, bundles vs. single items

Don’t Make These Common Mistakes

Testing too many things at once
Using too small a sample size (you need enough data to learn)
Ignoring your results just because the winner surprised you
Testing things that don’t matter to your audience (like fancy graphics if your list responds better to plain text)