Sample Size Calculator - Free Online A/B Test Sample Size Calculator

MKT-022 · Power analysis · Multi-variant Bonferroni · Duration estimate · Client-side

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Plan your experiment sample size

Normal approximation for two-proportion tests; Bonferroni adjustment for multiple variants vs control. Optional daily traffic estimates calendar days. All processing runs in your browser. Free tools hub.

Baseline conversion rate (%)

Minimum detectable effect

Variant rate = baseline × (1 + MDE/100).

Statistical significance

Statistical power

Number of variants (total arms)

Include control in the count.

Daily eligible traffic (optional)