Free A/B Testing Tools
A/B Testing Calculators
Plan statistically significant experiments with our free calculators. No signup required.
Sample Size Calculator
Calculate exactly how many visitors you need for statistically significant A/B test results.
95% confidence level
80% statistical power
Instant results
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Test Duration Calculator
Find out how long to run your A/B test based on your traffic and conversion goals.
Traffic-based estimates
MDE calculations
Week recommendations
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ROI Calculator
Calculate the potential revenue impact and ROI of your A/B testing program.
Revenue projections
Compound lift analysis
Annual ROI
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Significance Calculator
Compute p-value, confidence interval, and uplift from visitors + conversions (A vs B).
P-value + CI
Absolute & relative uplift
SRM sanity check
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SRM Checker
Detect Sample Ratio Mismatch (SRM) to validate your experiment traffic split.
Chi-square p-value
Expected split support
Clear diagnosis
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Conversion Rate Calculator
Calculate conversion rate and uplift (absolute & relative) for A vs B.
Conversion %
Absolute pp diff
Relative uplift %
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