Sample Size Calculator
Free sample size calculator for A/B tests and surveys. Calculate the minimum sample size needed for statistically significant results.
How to Calculate Sample Size for A/B Tests
- 1 Enter your baseline conversion rate percentage
- 2 Set the minimum detectable effect (MDE) you want to detect
- 3 Choose your confidence level (typically 95%)
- 4 Set the statistical power (typically 80%)
- 5 View the required sample size per variation and estimated test duration
Frequently Asked Questions
Is my code or data stored anywhere? ▼
No. All developer tools process data locally in your browser. Nothing is sent to any server or logged.
Can I use these tools offline? ▼
Yes! After the initial page load, most developer tools work without an internet connection.
Are there API limits? ▼
No limits. Since processing happens in your browser, you can use the tools as much as you need.
Is the output compatible with production use? ▼
Yes. Our tools produce standard-compliant output suitable for production environments.
🔒 Instant results, faster than AI. No signup. 100% private.
Last updated: January 15, 2026 · v2.1