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Talk to me, not a sales rep15 minutes · Free · No commitment
Talk to me, not a sales rep15 minutes · Free · No commitment
Compare two variants with confidence using p-value and statistical power outputs for faster A/B decisions.
Run the calculator to see statistical significance, p-value, and test power.
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You need four core values: control visitors (A), control conversions (A), variation visitors (B), and variation conversions (B). These inputs allow the calculator to compare conversion rates and compute significance.
Use test type and confidence level settings. One-sided tests whether variant B is better than A. Two-sided tests whether B is different from A (better or worse). Confidence level options are 90%, 95% (standard), and 99%.
The calculator returns a clear significance outcome, conversion rates for both variants, relative difference, statistical power, and p-value so you can assess both direction and reliability of the result.
Conversion rate is calculated as conversions divided by visitors for each variant. Control rate = control conversions / control visitors. Variation rate = variation conversions / variation visitors. Results are shown as percentages.
The p-value is the probability of seeing results at least this extreme if there were no true difference between variants. Lower p-values indicate stronger evidence against the null hypothesis.
A test is statistically significant when p-value is less than (1 - confidence level). For example, below 0.05 at 95% confidence, below 0.10 at 90%, and below 0.01 at 99%.
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