Online calculators

Indicate the proportion (percentage) on which you want to calculate your margin of error. This number should be between 0 and 100 (percentage). To ensure the most conservative estimate, it is standard practice in the industry to use a «p» value of 50% (when the result is unknown) because it is at this level that the margin of error is at its maximum. The closer to 0 or 100 your percentage is, the smaller your margin of error will be for a given sample size.

The population is the entire group of individuals that you want information about. Indicate the size of the total population from which your sample will be drawn. Note that, with the exception of very small populations, called finite populations, the size of the population has little to no impact on the margin of error. This is even truer in the case of very large populations.

This is the level (percent) at which you want to have confidence in the results. Select the confidence level you are willing to tolerate. For example, at a 95% level (or 19 times out of 20) and with a margin of error of 3%, you can be confident that there is only a 5% chance that your survey results will be more than 3% lower or 3% higher than the actual result. In other words, there is a 95% chance that the estimate from the sample will be within + or - 3% of the true percentage.