A/B Test Sample Size Calculator
Free tools / Cordell Digital
A/B Test Sample Size Calculator
Approximate equal-arm sample sizes for a two-sided 5% significance level. Relative lift differs from percentage-point lift. Plan independent visitors and a fixed test duration.
Your result
How to use this calculator
Use figures from the same reporting period and the same attribution scope. Sample inputs are hypothetical examples. Results describe the inputs you provide; they are not industry benchmarks or promises of future performance.
Calculation method
Approximate equal-arm sample sizes for a two-sided 5% significance level. Relative lift differs from percentage-point lift. Plan independent visitors and a fixed test duration.
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