Experimentation & CRO

A/B Testing Sample Size Calculator

Calculate exactly how many visitors and days your A/B test requires to reach true statistical significance (Adobe Target Benchmark).

Statistical Rigor: This calculator uses a two-sided Z-test for proportions with a fixed 95% confidence interval (α = 0.05). It prevents stopping tests early due to false positives (random sampling noise).

Baseline Conversion Rate (%):

2.0%

Minimum Detectable Effect (MDE %):

10% (Expected Variant: 2.20%)

Desired Statistical Power (β):

80% Statistical Power

Estimated Daily Page Traffic (Visitors/day):

5,000 visitors/day

Your A/B Test Dimensioning:

            Required Sample per Variation (A or B):
            156,480
          

Total Experiment Sample Size (A + B): 312,960

Estimated Test Duration: 63 days

RInC Data CRO Tip: If the estimated test duration is too long for your business window, we recommend increasing the MDE by testing bolder hypotheses (e.g., offer redesign or checkout simplification) or increasing traffic allocation.

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