What is Margin of Error?

The margin of error (MoE) is a statistic expressing the amount of random sampling error in survey's results. It asserts a likelihood (usually 95%) that the result from a sample is close to the number one would get if the whole population had been queried.

How does sample size affect MoE?

Increasing sample size reduces the margin of error. However, the returns diminish - to halve the MoE, you typically need to quadruple the sample size.

What does '95% confidence' mean?

It means if you repeated the survey many times, 95% of the calculated intervals (result ± MoE) would contain the true population value.

What is 'proportion'?

Proportion (p) is the percentage of the sample that chose a particular answer. 50% (0.5) gives the maximum margin of error, so it's often used as a conservative estimate if the true proportion is unknown.

Margin of Error Calculator

Calculate the margin of error for survey results and polls.

Confidence Level

Sample Size (n)

Proportion % (p)

Use 50% for maximum margin of error

Population Size (N)

Leave 0 for infinite population

Margin of Error

±0%

Result range: 0% – 0%

Interval Visualization

50%

Z-Score

Sample Size

1,000

Confidence

95%

Documentation

Margin of Error Formula

The margin of error is calculated using the Z-score for the confidence level and the standard error of the proportion.

Standard Error

Margin of Error

Finite Correction

Frequently Asked Questions

How to Use

About the Margin of Error

What it calculates

This margin of error solves mathematical and statistical problems using standard formulas. Calculate margin of error for surveys and polls.

When to use it

Use for homework, data analysis, exam prep, or quick verification of manual calculations.

Example

Adjust the inputs above to model your specific scenario with the Margin of Error.

Explore More

Margin of Error Calculator

±0%

Interval Visualization

Margin of Error Formula

About the Margin of Error

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