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Free A/B testing tools.

Two small calculators for the two questions every A/B test raises. No account, and they run in your browser: what you type into them is never sent anywhere.

A/B test significance calculator

Is your result real, or luck? Enter visitors and conversions for two versions and get a plain verdict, the p-value, lift and 95% ranges.

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A/B test sample size calculator

How many visitors does your test need, how long will it take, and what can your traffic detect? Plan the test before you start it.

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Keep the test next to the rest of your work.

Cleo keeps A/B tests in its Testing tab alongside the clients, tasks and dates they come from: numbers from your site or logged by the day, a target number of visitors, and a verdict in plain words. Free to start, no card.

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