Sample Size Calculator
Estimate required sample size using z (normal approximation). Optionally apply finite population correction (FPC).
About This Calculator
The Sample Size Calculator determines how many observations you need for statistically valid results. It considers confidence level, margin of error, and population size.
How to Use
- Enter the desired Confidence Level
- Enter the acceptable Margin of Error
- Optionally enter the Population Size
- Click Calculate to see required sample size
Practical Use Cases
- Survey Design: Plan adequate sample sizes
- Research: Ensure statistical power
- Quality Control: Determine inspection quantities
- Market Research: Size customer surveys
- Clinical Trials: Plan participant recruitment
? Frequently Asked Questions
How accurate is this
This calculator uses standard formulas and provides accurate results for typical use cases. For professional or critical applications, always verify results with certified professionals or official sources.
Is this calculator free to use?
Yes, this Statistics Sample Size Calculator is completely free to use with no registration required. You can use it as many times as needed without any limitations.
Can I use this on mobile devices?
Absolutely! This calculator is fully responsive and works perfectly on smartphones, tablets, and desktop computers.
How do I interpret the results?
The results are displayed clearly with appropriate units. Refer to the "About This Calculator" section for detailed information.