Sample Size Calculator

Quickly estimate the minimum sample size you need for your psychology experiments and research projects. This simple calculator helps you determine sample size based on effect size (Cohen’s d), desired statistical power, significance level (alpha), and test type (t-test or ANOVA).

Ideal for psychology students, dissertation writers, and social science researchers. Understand how effect size, power, and alpha affect sample size — and receive clear confidence intervals and standard deviation estimates. No login, no complex formulas — just fast, reliable guidance for study planning.

Note: This tool uses simplified formulas for quick estimation. For complex designs, consider using GPower.

Disclaimer

This tool is designed to assist psychology students and researchers with calculating sample size. While we strive for accuracy, the output provided is for guidance purposes only.

The creators of this tool are not responsible for decisions made based on its output. Always ensure your work aligns with the requirements of APA academic or professional standards.