Variance Calculator

Find the sample and population variance of a data set.

⏱ Updated: 17 Sep 2026

Calculator

Free variance calculator: find the population and sample variance of a data set.

Sample Variance
Population Variance
Mean
Count

Use sample variance when your numbers are a sample from a larger population (the common case); use population variance only when your numbers are the entire population.

Enter a list of numbers to calculate the sample and population variance.

How to Use the Variance Calculator

Identical input to the Standard Deviation calculator — variance is just that number before the square root, shown here directly instead of derived.

Unsquared, the distances between each data point and the mean always cancel out to exactly zero — the positives and negatives balance no matter how spread out the data actually is, which makes that version useless as a spread measurement. Squaring first fixes that, forcing every term positive before they're averaged.

variance = Σ(x − mean)² ÷ n           (population)
variance = Σ(x − mean)² ÷ (n − 1)     (sample)

This Variance Calculator reports both versions. Standard deviation, if you've seen that term too, is just variance's square root — variance stays in squared units ("68 squared dollars" doesn't mean much intuitively), while standard deviation returns to the original scale, which is why it's usually the number people actually quote.