The hardest part of A/B testing isn’t running the test. It’s deciding what to test. You know your page could convert better. You just don’t know where to start.
These ideas give you a starting point. Filter by page type, expected impact, and effort to find tests that make sense for where you are right now. Every idea here has moved the needle for someone. The question is which ones fit your product and audience.
How to pick your first test
Start with high impact plus easy effort. These are single-change tests, things like a headline rewrite or moving a CTA button, that can produce measurable results without a designer or developer. Filter for those first.
Test the biggest lever, not the smallest detail. Your headline is probably 10x more impactful than your button color. The hierarchy of conversion elements goes: value proposition first, then layout, then copy, then design details. Work top-down.
Build a hypothesis before you test. “Let’s try a different headline” is a guess. “If we rewrite the headline to focus on the result instead of the feature, signups will increase because visitors care about outcomes, not capabilities” is a hypothesis. Good hypotheses have three parts: what you’re changing, what you expect to happen, and why. The experiment design guide covers this in detail.
Use the ICE framework to prioritize. If you have multiple ideas, score each one on Impact (how much could this move the needle?), Confidence (how sure am I this will work?), and Ease (how fast can I build and launch this?). Multiply the scores. Test the highest-scoring idea first.
Run one test per page at a time. Multiple changes on the same page make it impossible to know what worked. If you want to test several things, either test them one at a time or use a multivariate testing approach (which needs a lot more traffic).
FAQ
What should I A/B test first?
Your headline. It’s the first thing visitors see and the biggest single lever on most pages. A headline that describes the result your visitor gets (“Get 3x more leads”) outperforms one that describes what the product does (“AI-powered marketing platform”) in almost every test. After headlines, test your CTA copy and placement. Then test page layout (long vs. short, single column vs. two column). Save design details (colors, fonts, button shapes) for last. They rarely move the needle as much as copy and structure.
How many A/B tests should I run at once?
One test per page. Running two tests on the same page creates interaction effects where the results of one test contaminate the other. You can run tests on different pages simultaneously (homepage test + pricing page test), as long as there’s no overlap in the conversion funnel. Use the sample size calculator to estimate how long each test needs.
What’s the difference between high and low impact tests?
High impact tests change something fundamental: headline, value proposition, page layout, pricing structure, or entire sections of content. They tend to produce bigger lifts but can be riskier. Low impact tests change details: button text, image choice, testimonial placement. They’re safer and faster to implement, but the lifts are usually smaller. Start with high impact ideas if your page has never been tested. Move to lower impact once the big wins are captured.
How do I prioritize A/B testing ideas?
Use the ICE framework. For each idea, score three things from 1 to 10: Impact (if this works, how much will it move conversions?), Confidence (based on data or research, how sure am I this will work?), and Ease (how quickly can I build and launch this?). Multiply the three scores. Test the highest total first. This prevents the common trap of testing easy, low-impact things while ignoring the hard, high-impact ones. The CRO strategy guide covers prioritization frameworks in more detail.
Can I use these ideas on any website?
Yes. The ideas are organized by page type (homepage, pricing, landing page, checkout, etc.), but the underlying principles apply everywhere. A headline test on a SaaS pricing page uses the same logic as a headline test on an e-commerce product page. Adapt the specifics (copy, images, social proof) to your audience and product. The psychology behind why these tests work, things like social proof, scarcity, and clarity, is universal.
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