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Margin of Error Calculator

Survey margin of error from sample size and proportion.

Estimate the margin of error of a survey result from sample size, observed proportion, and confidence level.

Daniel Oh By Daniel Oh
Published Last reviewed 1 min read

Inputs

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

MoE = z · √(p(1−p) / n), where p is the observed proportion and z is the confidence multiplier.

In depth

Estimate the margin of error of a survey result from sample size, observed proportion, and confidence level.