Margin of Error: n = 500, p = 0.5, 95% Confidence
A sample of 500 with p = 0.5 at 95% confidence has a margin of error of approximately ±4.4%.
How to use this tool
- Enter sample size (n), proportion (p) and z* (confidence level) in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your margin of error and the full breakdown beneath it.
Find the margin of error for a mid-sized survey of 500 respondents at 95% confidence level.
Frequently asked questions
- What is the margin of error?
- The margin of error quantifies the uncertainty in a sample proportion estimate. A MOE of ±3% at 95% confidence means the true proportion is within 3 percentage points of the observed proportion 95% of the time.