Sample Size & Margin of Error Calculator
Determine the minimum sample size for your research or calculate the margin of error for your survey data
Sample Size Calculator
Margin of Error Calculator
Sample Size Calculator
n = (Z² * p * (1-p)) / E²
This calculator helps you determine the minimum number of participants needed in your survey or experiment to achieve statistically significant results. The formula accounts for your desired confidence level, margin of error, and population proportion.
1% (Precise)
20% (Less Precise)
1%
99%
Sample Size Results
Required Sample Size:
385
Confidence Level:
95%
Margin of Error:
±5%
Population Proportion:
50%
Sample Size vs. Margin of Error
Margin of Error Calculator
E = Z * √(p(1-p)/n)
This calculator helps you determine the margin of error for your survey results based on your sample size, confidence level, and population proportion. The margin of error indicates the range within which the true population value is likely to fall.
1%
99%
Margin of Error Results
Margin of Error:
±5.0%
Confidence Level:
95%
Sample Size:
385
Population Proportion:
50%
Confidence Interval:
45% to 55%
Confidence Interval Visualization
How to Use This Calculator
- Sample Size Calculator: Use when planning a study to determine how many participants you need. Input your desired confidence level, margin of error, and estimated population proportion.
- Margin of Error Calculator: Use after collecting data to determine the accuracy of your results. Input your confidence level, sample size, and population proportion.
- Confidence Level: Represents how confident you can be that the population parameter lies within your margin of error (95% is standard).
- Population Proportion: Your estimated percentage of the population that has the characteristic you’re measuring (50% gives the most conservative estimate).
- Population Size: Only required when your sample represents more than 5% of a finite population.