Margin of Error Calculator

Can you rely on your survey results? By calculating your margin of error (also known as a confidence interval), you can tell how much the opinions and behaviour of the sample you survey is likely to deviate from the total population. This margin of error calculator makes it simple.

*This margin of error calculator uses a normal distribution (50%) to calculate your optimum margin of error.

What is a margin of error?

Your margin of error is the possible range of values above and below the response you obtain from a given sample. As an example, imagine that you are trying to decide between Name A and Name B for a new product your company planned to launch and your target market (the "population") consists of 400,000 potential customers. If you surveyed 600 of them (your "sample size") and 60% of them liked Name A, could you rely on your survey results?
Using the margin of error calculator with a confidence level of 95% (meaning there’s a 95% probability that your sample accurately reflects the attitudes of your potential customers), you’ll see that the margin of error is 4%. That means there’s a 95% probability that between 56% and 64% of your target audience will prefer Name A.
We arrived at 56 and 64 by adding and subtracting the margin of error from your sample’s response to your survey.

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Is your margin of error too big?

If you calculate your margin of error and it feels too big, you’ll need to increase your sample size by sending your survey to more people. With SurveyMonkey Audience, we make it easy to obtain the sample you need. We have millions of people who are ready to take your surveys. Just give us your criteria and we’ll provide you with answers you can rely on in just a few days.
If you want to calculate your sample size, check out our sample size calculator.