Free calculator

Margin Of Error Calculator

Free Margin Of Error Calculator with instant browser-based results and a clear calculation breakdown.

Margin of Error Calculator

Calculate the margin of error for survey or poll results

Confidence Level How confident you want to be in your results

Sample Size (n) Number of people surveyed

Please enter a valid sample size (at least 1)

Sample Proportion (p) Proportion with the characteristic (0 to 1, or use 0.5 for maximum margin)

Please enter a value between 0 and 1

Margin of Error

±0.00%

What This Means

Formula Used

MOE = Z × √(p × (1-p) / n)

Where:

• Z = Z-score for the confidence level

• p = Sample proportion

• n = Sample size

Understanding the Result

The margin of error indicates the range within which the true population value likely falls. A smaller margin of error means more precise results. You can reduce the margin of error by increasing your sample size or accepting a lower confidence level.

Want to understand the calculation?

See examples, formula notes and limitations.

Read the guide