# 25: Needed Sample Size for a Confidence Interval for a Population Proportion Calculator

- Page ID
- 8348

Sample Size Calculator

Fill in the error bound (E) and the confidence level (CL) written as a decimal, for example a 95% confidence level is 0.95. If there is an estimate for the population proportion, check the "Have Estimate for p" radio button and then fill in the estimate in the p box that appears. Then hit "Calculate n" and the needed sample size will be calculated for you.

No Estimate for p | Have Estimate for p | Estimate for p: | E: | CL: | n: |