Variance Calculator

Sample variance divides by n − 1 (Bessel's correction) — it's the right choice when your data is a sample from a larger population. Population variance divides by n and is correct only when you have data for the entire population. Most real-world stats use the sample formula.

Comma-separated, space-separated, or one per line — all work. The calculator strips empty entries and ignores anything that isn't a valid number. Negative numbers and decimals are fine.

Standard deviation is the square root of variance. The variance is in the squared units of your data; the standard deviation is in the original units, which is why it's usually easier to interpret.

When every value in your dataset is the same, there's no spread — both variance and standard deviation are exactly zero. With a single value, sample variance is undefined (you'd divide by zero); population variance is zero.