Required Sample Size
385
With 95% confidence and 5% margin of error, you need 385 responses for an infinite population.
Choose the right sample size to ensure your survey or experiment yields reliable, actionable results. This tool supports margin of error, power analysis, and finite population correction.
95% is standard for most business and academic research. Use 99% for critical decisions.
5% is typical. For precise estimates, use 2‑3%; for exploratory research, 10% may be acceptable.
Sample size is largest when the proportion is 50% (most conservative). Use 50% if unsure.