Sample Size: 95% Confidence, 3% Margin of Error
For 95% confidence and a tighter ±3% margin of error, you need approximately 1068 respondents.
How to use this tool
- Enter expected proportion (p), z* (confidence level) and margin of error (e) in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your required sample size (n) and the full breakdown beneath it.
Determine how many survey participants you need for 95% confidence and a narrow ±3% margin of error.
Frequently asked questions
- Why use p = 0.5 when the proportion is unknown?
- p × (1−p) is maximised at p = 0.5, giving the most conservative (largest) required sample size. If you have a prior estimate of p, use it to get a smaller required n.