A/B Testing Sample Size Calculator Baseline Conversion Rate (%) Current conversion rate of the control (e.g. 3.5%) Minimum Detectable Effect (%) Minimum change worth detecting (e.g. 20 for 20%) Confidence Level (%) How sure you want to be (95% is standard) 90%95%99% Statistical Power (%) Chance of detecting an effect if one exists (80% typical) 80%85%90% 🔍 Calculate Sample Size 📊 Required Sample Size Per Variant: