Margin of Error Calculator

Choose a mean or proportion, confidence level, sample size, and sample information to calculate the margin of error.

Estimate type

Confidence

Sample size (n)

Sample SD (s)

—Margin of error

—Critical value

—Standard error

—Degrees of freedom

—Two-sided confidence interval margin.

How to use this Margin of Error Calculator

Calculate a confidence-interval margin of error for a mean or proportion. Enter your values above and the result is calculated directly in your browser. No account is required.

Fast answer, clear inputs

This tool is built around one job: give the answer quickly without forcing a signup or hiding the result. Related tools are linked nearby when the next calculation or conversion is useful.