A/B Test Sample Size & Significance Calculator

Determine A/B test statistical significance and minimum sample size using a two-proportion z-test.

Sample size (Control A)

Conversions (Control A)

Sample size (Variant B)

Conversions (Variant B)

Confidence level (%)

Tab to move between fields

Relative lift (%)

20%

Conversion rate A (%)3%

Conversion rate B (%)3.6%

Z-score1.68

Significant (0/1)0

Min sample per variant13,915

How to Use This Calculator

Enter sample sizes and conversion counts for Control A and Variant B.
Set the desired confidence level (typically 95%).
Review Conversion Rate A (%), Conversion Rate B (%), Relative Lift (%), Z-Score, and Significant flag.
If the result is not statistically significant, collect more data before making product decisions.

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