🎯 Sample Size Calculator
Required sample size for surveys and experiments
About this calculator
The Sample Size Calculator finds how many responses a survey or study needs. Enter your desired confidence level, margin of error, and estimated population proportion (use 50 percent for the safest, largest sample); it applies the standard formula with an optional finite-population correction. Smaller margins and higher confidence both demand bigger samples.
Tip: doubling precision quadruples the sample size — so decide what margin of error you can actually live with before fielding, because chasing 1 percent precision on a casual survey wastes time and money.