Sample Size Calculator
Determine required sample size for surveys and experiments with specified margin of error and confidence level
About this calculator
Our Sample Size Calculator helps researchers, marketers, and analysts determine the optimal number of participants needed for statistically reliable surveys and experiments. By inputting your desired confidence level and margin of error, you can calculate the minimum sample size required to achieve meaningful, actionable results. This tool eliminates guesswork and ensures your research meets statistical standards while avoiding costly over-sampling or unreliable under-sampling that could compromise your findings.
How to use
Enter your target population size, desired confidence level (typically 90%, 95%, or 99%), and acceptable margin of error percentage. The calculator will instantly compute the minimum sample size needed for your study. Higher confidence levels and lower margins of error require larger sample sizes for statistically valid results.
Frequently asked questions
What confidence level should I choose?
95% confidence level is standard for most research. Use 99% for critical decisions requiring higher certainty, or 90% for preliminary studies.
How does margin of error affect sample size?
Lower margin of error requires larger samples. A 3% margin needs more participants than 5% to achieve the same reliability.
Do I need to know my exact population size?
For large populations (over 20,000), the exact size has minimal impact. You can use 'infinite' for most surveys.