Sample Size Calculator

Calculate a proportion-based survey sample size with optional finite-population correction and response-rate planning.

Confidence level

Margin of error (%)

Expected proportion (%)

Population size (optional)

Expected response rate (%)

—Required responses

—People to invite

—Large-population n₀

—Finite-population effect

—Proportion estimate: n₀ = z²p(1−p)/e²; optional finite-population correction is then applied.

This is a general survey/proportion planning calculator, not a substitute for a study-specific statistical power analysis.

How to use this Sample Size Calculator

Estimate survey sample size from confidence level and margin of error. Enter your values above and the result is calculated directly in your browser. No account is required.

Fast answer, clear inputs

This tool is built around one job: give the answer quickly without forcing a signup or hiding the result. Related tools are linked nearby when the next calculation or conversion is useful.