A/B Test Calculator

Plan your experiments with the right sample size, then evaluate results with statistical confidence.

Pre-test: Sample Size Calculator

Calculate how many visitors you need for your A/B test to reach statistical significance.

Confidence Level

80%85%90%95%99%

Statistical Power

60%65%70%75%80%85%90%95%99%

Number of Variants

Baseline Conversion Rate (%)

Expected Absolute Increase (%)

Sample size per segment

2,791

Total sample size

5,582

across 2 variants

Evaluate your A/B test results and determine statistical significance.

Confidence Level

80%85%90%95%99%

Number of Variants

Variant	Visitors	Conversions	Rate	Confidence Interval
A			2.40%	[2.01% — 2.86%]
B			3.00%	[2.56% — 3.51%]

No significant difference between variant A and variant B at 95% confidence. You may need more data.