A/B Test Calculator

Estimate lift and statistical significance for A/B tests.

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What This Calculator Does

Estimate lift and statistical significance for A/B tests.

It combines Control Visitors, Control Conversions, Variant Visitors, Variant Conversions to estimate Lift, Control Rate, Variant Rate.

Formula & Method

For control and variant rates p_1=\frac{c_1}{n_1},\;p_2=\frac{c_2}{n_2}, lift is Lift\% = \frac{p_2-p_1}{p_1}\times100. Significance uses pooled proportion p=\frac{c_1+c_2}{n_1+n_2}, standard error SE=\sqrt{p(1-p)\left(\frac{1}{n_1}+\frac{1}{n_2}\right)}, z-score z=\frac{p_2-p_1}{SE}, and two-tailed p-value from the normal CDF.

Notation used in the formulas: R = Lift; x_{1} = Control Visitors; x_{2} = Control Conversions; x_{3} = Variant Visitors; x_{4} = Variant Conversions.

Method summary: inputs are normalized to consistent units, core equations are evaluated, then secondary values are derived and rounded for display.

Use this calculator for quick scenario analysis. Start with baseline values, change one driver at a time, and compare how sensitive the results are to each input shown above.

Inputs Used

Control Visitors: Used directly in the calculation.
Control Conversions: Used directly in the calculation.
Variant Visitors: Used directly in the calculation.
Variant Conversions: Used directly in the calculation.

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