This free sample size calculator determines the sample size required to meet a given set of constraints. Also, learn more about population standard deviation.

Calculate sample size with our free calculator and explore practical examples and formulas in our guide to find the best sample size for your study.

You can use this free sample size calculator to determine the sample size of a given survey per the sample proportion, margin of error, and required confidence level.

Jan 9, 2026 · To calculate sample size, first find the population size, or number of people taking your study, and margin of error, which is the amount of error you'll allow in your results.

Jan 9, 2025 · If you are a clinical researcher trying to determine how many subjects to include in your study or you have another question related to sample size or power calculations, we developed this …

Whether you're comparing means (paired/unpaired), proportions, multiple groups (ANOVA), categorical associations (chi-square), or building predictive models (multiple regression), this calculator will help …

May 15, 2025 · Learn how to calculate survey sample sizes by exploring margin of error, confidence levels, population variability, and practical formulas.

In any research or survey, determining the right sample size is critical to obtaining reliable and statistically significant results. The Sample Size Calculator is a simple yet powerful tool designed to …

Calculate the required sample size for your statistical study based on confidence level, margin of error, and population parameters. What are you estimating? When the population size is known and finite, …

To calculate a sample size, you need to make three assumptions. Here is what they actually mean. "How sure do I need to be?" 95% is the industry standard. It means if you repeated the survey 20 …