Most marketers send emails and hope for the best. Very few test, learn, and improve every single time.
This guide is for anyone who’s ready to start email split testing.
We’re going deep into email split testing: what it is, how it works, what to test, how to run it, and how to actually get better results from your list.
Not theory. Not vague tips. Just a full breakdown of:
- What really moves the needle in email performance
- How to set up split tests that give you clear answers
- Why most email tests fail — and how to avoid that
- A template you can copy, and examples you can steal
By the end, you’ll know how to send smarter emails — and if you’re using Encharge, you’ll be able to set all this up in minutes.
Contents
What is Email Split Testing?
Answer: Email split testing is the process of sending two or more versions of an email to different segments of your audience to see which one performs better.
You might test subject lines, content, images, CTAs — anything that could impact how people engage with your emails.
The goal is simple. Find out what works, and use it to get better results.
- It’s not about guessing or going with your gut.
- It’s about letting data decide what gets you more opens, clicks, and revenue.
Here’s how split testing really works in email marketing:
Most marketers talk about A/B testing — but split testing is the same thing.
The only difference is the name. You’re comparing multiple versions of an email to improve performance.
That’s it. No jargon, just smarter email marketing.
Split Testing vs A/B Testing in Email Marketing: The Differences
Split testing and A/B testing mean the same thing.
You’re comparing two (or more) versions of an email to see which one performs better. Some tools call it A/B testing, while others call it split testing.
The method is identical, with the process being:
- You change one variable
- You send both versions
- You measure what gets more opens, clicks, or conversions
The only real difference is how people talk about it — which brings us to this table, which hopefully will help you understand the differences between the two terms:
| Email Term | A/B Testing | Split Testing |
|---|---|---|
| Commonly used in | Technical or analytics-focused tools | Email marketing platforms |
| Typical usage | 2 versions (A and B) | 2 or more versions (A/B/C…) |
| Name implies | Strictly two variants | Flexibility to test multiple variants |
| Perceived complexity | Slightly more technical | More marketer-friendly |
| Real-world difference | None — same testing process | None — same testing process |
We’re using “split testing” in this guide because it’s clearer, broader, and less tied to a specific setup. Whether you’re testing a subject line in a broadcast or two full flows against each other — it’s still split testing.
Same idea, different name.
What matters is getting better results from every email you send.
Related: We have a separate guide that deeply explains email A/B testing.
Why Should You Split Test Emails?
The full answer: You should split test your emails to improve performance and drive more revenue by identifying which version of your message performs best.
Though shortly, because guessing is expensive.
Every time you send an email without testing, you’re making assumptions — about your subject line, your offer, your copy, your audience. Sometimes you get it right. Most times, you leave results on the table.
This visual helps reveal the true potential of split testing:
Split testing removes the guesswork. You find out what actually works, not what you think will work.
It’s how you:
- Get higher open rates by testing subject lines
- Get more clicks by trying different CTAs or layouts
- Get more sales by improving every part of your funnel, one test at a time
The goal isn’t just “better emails”, but earning more revenue from the exact same list.
That’s the leverage split testing gives you — and once you see it work, you won’t go back.
8 Email Split Testing Examples You Can Steal For Free
Split testing only works if you know what to test — and why it matters. Below are the most valuable email elements to experiment with, plus ideas to get you started.
Test one thing at a time and keep the rest consistent. That’s how you learn what actually moves the needle.
1. Subject Line
The subject line is the gatekeeper. If it doesn’t work, nothing else matters — your email doesn’t get opened, and your offer never gets seen.
Even small tweaks here can drive big changes in performance. That’s why subject line testing is the most common and most impactful email test.
What you can test:
- Length: Short, punchy lines vs. longer descriptive ones
- Personalization: Adding
{{FirstName}}or other dynamic fields - Tone: Serious vs. playful, formal vs. casual
- Structure: Questions, statements, emoji use, symbols, punctuation
- Clarity vs. curiosity: Straightforward offers vs. intriguing hooks
Why it matters: Subject line testing helps you understand how your audience reacts to different types of messaging.
For example: Some readers might respond better to urgency (“Last chance to save 30%”), while others might click on something unexpected (“{{FirstName}}, this isn’t a normal update”).
Running structured tests helps you identify consistent patterns that increase your open rate over time.
2. Preview Text (Preheader)
The preview text is the line of copy that shows up next to your subject line in most inboxes. Many marketers ignore it, but it plays a major role in boosting (or killing) your open rate.
What you can test:
- Reinforcing the subject line vs. contrasting it
- Plain copy vs. emojis or creative formatting
- Teasing the email content vs. restating the value
- Including a CTA (e.g., “See your stats”)
Why it matters: Think of preview text as your second shot at convincing someone to open. If your subject line piques interest, the preview text can close the deal. Testing different combinations helps you dial in the right one-two punch for your inbox strategy.
Example:
- Subject: “
{{FirstName}}, see what changed this week” - Preview A: “Your growth report is live”
- Preview B: “One mistake to avoid before Friday”
Even subtle changes here can shift open rate by several percentage points.
Learn how you can set the preview text in Encharge, for free.
3. Sender Name
Before reading your subject line, people check who it’s from. It’s often the first filter people use to decide whether to open or ignore an email.
What you can test:
- Brand name only (e.g. Encharge)
- Real person only (e.g. David Ch)
- Hybrid (e.g. David from Encharge)
- Different senders for different types of emails (e.g. support vs. sales)
Why it matters: Trust is everything in email. Testing sender names helps you identify which type of branding your audience feels most comfortable engaging with.
A real person might drive higher opens in a welcome sequence, while your brand name might perform better for product updates.
Example: We’ve seen higher engagement using names like “Laura at Encharge” in onboarding emails, while “Encharge” alone performs better in monthly updates.
Your list might react differently — test and find out.
4. Email Copy
Once the email is opened, the copy decides whether the reader stays or bounces. Every sentence has a job: hook attention, communicate value, and move the reader toward action.
What you can test:
- Length: Short vs. detailed explanations
- Style: Paragraphs vs. bullet lists
- Tone: Friendly vs. direct, funny vs. serious
- Voice: First-person (“I want to show you…”) vs. brand voice
- Framing: Pain-first vs. benefit-first copy
- Use of personalization: Dynamic blocks, behavior-based content
Why it matters: Your audience might not need more content — they might just need clearer, more relatable copy. Split testing copy helps you shape messaging that connects and converts.
For example: Testing urgency-focused framing (“This offer expires in 24 hours”) vs. outcome-focused framing (“Start automating your campaigns today”) reveals which angle actually drives clicks.
5. CTA (Call-to-Action)
The CTA is the tipping point.
It turns attention into clicks. Every part of it — wording, design, placement — can affect whether someone takes action.
What you can test:
- Button vs. text link
- Wording: “Start Free Trial” vs. “Get Access” vs. “See Pricing”
- Position: Top vs. middle vs. bottom vs. multiple placements
- Size and design: Minimalist vs. attention-grabbing
- CTA frequency: One call to action vs. several
Why it matters: You might write the perfect email — but if the CTA doesn’t land, it won’t convert.
Some audiences prefer softer CTAs like “Learn More”.
Others respond to assertive prompts like “Try It Free Now.” Testing helps you find your default high-performing CTA across campaigns.
6. Layout & Design
Good design helps readers focus. Bad design gets in the way. You don’t need flashy visuals, you need clarity and flow.
What you can test:
- Plain text vs. branded automated HTML templates
- Image size and placement
- Mobile-first layouts vs. desktop-first
- Font type, size, and color schemes
- Spacing, dividers, and visual hierarchy
Why it matters: Some audiences love clean, visual emails. Others trust plain-text formats that feel like a personal note. If your emails look great but don’t perform, layout might be the silent killer.
Example: You might find that reducing image use increases click-throughs. Or that mobile users bounce more on multi-column designs.
How to Run a Successful Split Test in Email Marketing
Answer: To split test an email, you need a tool like Encharge to create two versions, choose your test metric, and let the platform test automatically.
Whether you’re testing personalization elements in a broadcast or full logic branches in an automated flow, everything is built in — no hacks, no spreadsheets.
Here’s how it works:
- Pick what to test — subject lines, content, CTAs, or entire flows
- Create your two (or more) variants directly inside the editor
- Add a Split Step (in flows) or use A/B blocks (in broadcasts)
- Set how to split the audience — 50/50 or your own ratio
- Choose your goal metric (open rate, clicks, or custom event)
- Send or activate your flow — Encharge tracks performance automatically
- Encharge sends the winning version to the rest of your list (optional)
- Review results in real time and apply the insights in future emails
It takes minutes to set up, and every test gives you real answers — not assumptions.
If you’re serious about improving your email performance, Encharge makes split testing the easiest win in your workflow.
7 Best Practices for Email Split Tests
Split testing is simple in theory — but it’s easy to mess up in practice. If you want accurate results and meaningful improvements, you need to follow a few rules.
Here are seven proven best practices that’ll save you time, avoid false results, and help you make better decisions.
1. Test One Variable at a Time
The biggest mistake people make is changing too many things at once. If your subject line, CTA, and layout are all different between versions A and B, you won’t know what made the difference.
Keep your test focused on one variable.
- Want to improve your open rate? Test just the subject line.
- Want more clicks? Try different CTA wording.
Change one thing, measure the impact, and apply what works.
2. Let the Test Run Long Enough
Don’t end your test early just because one version pulls ahead in the first hour. Early data is often misleading — especially with smaller lists.
Give your test enough time to reach statistical significance.
For most campaigns, this means at least a few hours to a full day. If you’re testing flows or behavior-based emails, you may need to let it run for a few days.
The goal is clarity, not speed.
3. Use a Large Enough Sample Size
If your list is too small, your results won’t be reliable. You might see a 10% lift from one variant — but that could just be random noise if only 40 people opened the email.
For basic tests, aim for at least a few hundred recipients per version. The larger your list, the more confident you can be in the result.
Encharge handles this automatically — but if you’re doing it manually, make sure the test is statistically valid before drawing conclusions.
4. Choose the Right Metric for Your Goal
Not every test is about open rate. It depends on what you’re optimizing for.
- Testing a subject line? Look at open rate
- Testing a CTA or layout? Focus on click-through rate
- Testing an offer? Measure conversions or replies
Define your success metric before launching the test — otherwise you’ll end up chasing numbers that don’t matter.
Related: Read more about the best email marketing KPIs.
5. Keep Your Timing Consistent
If version A is sent in the morning and version B in the afternoon, you’re not really running a test — you’re comparing two different send times.
Send both variants at the same time, or as close to it as possible. This ensures that external factors (like time of day, inbox competition, or mood) don’t skew your results.
Tools like Encharge automatically split your audience and control for timing, so you don’t have to think about it.
6. Document and Reuse What Works
Winning a test isn’t enough — the real value comes from applying the insight to future campaigns.
Keep a record of:
- What you tested
- What each variation looked like
- Which version won
- What you learned
Over time, you’ll build a library of what works for your audience — subject line formulas, CTA phrases, layouts that consistently convert.
This turns testing from guesswork into strategy.
7. Don’t Stop After One Test
Split testing is not a one-and-done exercise. What works today might flop in a month. New audiences, offers, or seasonal behavior can shift performance.
- Keep testing. Make it part of your process.
- Some tests will fail — that’s fine.
- The more you test, the more you learn, and the better your emails get.
The most effective teams don’t just test, they test consistently.
FREE Email Split Testing Template (Copy-Paste)
Planning split tests manually can get messy — especially if you’re changing multiple things across campaigns.
This template helps you stay focused, track your results, and apply what works. You can copy this into Notion, Google Sheets, or wherever you manage campaigns.
| Campaign | Element | Test A | Test B | Metric | Winner |
|---|---|---|---|---|---|
| Welcome Email | Subject Line | “Welcome to Encharge 👋” | “{{FirstName}}, you’re in” | Open Rate | A |
| Trial Activation | CTA Button | “Start Free Trial” | “Claim Your Spot” | Click-Through Rate | B |
| Newsletter #12 | Sender Name | “Encharge” | “Laura at Encharge” | Open Rate | B |
| Promo Blast | Layout | Visual template w/ header | Plain text layout | Replies | A |
How to use this template:
- Test one variable per row. If you change too many things, you won’t know what worked.
- Define your metric. Are you optimizing for opens, clicks, or replies? Start with a clear goal.
- Run the test long enough. Don’t declare a winner after 20 minutes. Give it time.
- Document the results. Reuse what wins. Over time, you’ll build a playbook that performs.
This template helps you test smarter and avoid random experiments that lead nowhere.
Bonus: Want to skip the table? Encharge lets you run these exact tests — subject lines, CTAs, layouts, and more — directly inside your campaigns.
You set up the variants. We track the results. The best version gets sent to the rest of your list, automatically.
Join me in the next section to see how it works!
Split Testing Manually? Encharge Automates Every Step
Split testing works, but only if you actually do it.Most marketers stop after a few tests because setting them up is slow, messy, and hard to track.
Encharge makes it simple: You choose what to test (subject lines, content, CTAs, even entire flows), and the platform handles the rest.
It splits, tracks performance, and sends the winning variant automatically.
No need for extra tools, manual analysis, or second-guessing.
What you get isn’t just convenience.
You get better email results: more opens, more clicks, and more revenue — without changing how you work.
Encharge removes the friction so you can focus on what matters: running smarter campaigns that bring in more money.
Conclusion: When to Split Test vs Just Sending It
You don’t need to split test every single email — some emails are transactional, others are time-sensitive. In those cases, speed matters more than testing.
But if you’re sending to a large list, promoting an important offer, or launching a core campaign — you should be testing. Even small improvements in open or click rates can compound into serious gains over time.
Here’s a simple rule:
- Split test when you want to improve performance
- Just send when the email is routine, urgent, or low-impact
Think of testing as a multiplier. If your email has the potential to move revenue, engagement, or growth — testing it is always worth the effort.
And with a tool like Encharge, the “effort” part disappears. Testing takes minutes, and results speak for themselves.
Email Split Testing FAQs
1. How many emails do you need to run a split test?
To run a valid email split test, you typically need at least a few hundred recipients per version. Smaller lists can still test, but the results may be less reliable. The larger your list, the more confident you can be in the outcome.
2. How long should you run an email split test?
An email split test should run for at least 4 to 24 hours, depending on your audience size and engagement speed. Ending the test too early can give you false results, especially if your list is small.
3. Can you split test more than two email versions?
Yes, you can split test more than two versions of an email.
This is often called A/B/C or multivariate testing. Just keep in mind that testing more variants requires a bigger list to get meaningful results.
4. Can you split test automated email flows?
Yes, you can split test automated email flows.
Tools like Encharge let you test entire flow branches, not just one-off campaigns — helping you optimize onboarding, re-engagement, and lifecycle sequences over time.
5. What is a good open rate for email split testing?
A good open rate for email split testing is typically 20% to 35%, but it depends on your industry and audience. Focus on improving your own benchmark with consistent testing rather than chasing generic averages.
Thank you so much for reading this,
David Ch
Head of Marketing at Encharge
