Sample Size Calculator
Determine the optimal sample size for your research study to ensure statistically significant results.
Study Parameters
If unknown, use 50% for the most conservative estimate
Recommended Sample Size
Visualization
Confidence Level
95%
Margin of Error
5%
About Sample Size Calculation
Confidence Level
The probability that your sample accurately reflects the population. Higher confidence levels require larger sample sizes.
Margin of Error
The range in which the true population value is expected to fall. Smaller margins require larger sample sizes.
Population Proportion
The estimated percentage of the population with a particular characteristic. Using 50% gives the most conservative estimate.
Sample Size Formula
For infinite populations: n = (Z² × p × (1-p)) / e²
For finite populations: n = n₀ / (1 + (n₀ – 1)/N)
Where: Z = Z-score, p = proportion, e = margin of error, N = population size, n₀ = sample size without correction