Variance Calculator

Variance is one of the most important numbers in statistics because it puts a single figure on something we can all see but struggle to quantify: how spread out a set of values really is. Two data sets can share the same average yet behave completely differently, one tightly clustered and predictable, the other wildly scattered, and variance is what separates them. This calculator takes any list of numbers and returns both the population variance and the sample variance, along with the mean, the standard deviation, the sum of squares and the count, so you can see exactly where the result comes from rather than trusting a black box. Variance works by measuring how far each value sits from the mean, squaring those distances so that positive and negative gaps do not cancel out, and then averaging them. Squaring also gives extra weight to the outliers that pull a data set apart. The only real decision you need to make is whether your numbers are the entire group you care about, in which case you use the population variance and divide by N, or a sample drawn from something larger, in which case you use the sample variance and divide by N minus 1. That small adjustment, known as Bessel's correction, stops a sample from understating the true spread. Paste or type your values below, separated by commas, spaces or new lines, and the calculator updates instantly. It is built for students checking homework, researchers summarising results, analysts cleaning data, and anyone who needs a fast, transparent measure of variability.

Calculate.co.nz is proud to be partnered with Premium Homes, a recognised leader in eco-friendly, sustainable, and energy-efficient homebuilding. With a dedicated team and award-winning experience, they create homes that prioritise health, comfort, and long-term performance. Their founders, Andrew and Kelly, set out to raise the standard of residential construction in New Zealand by combining practical building expertise with a clear commitment to doing things better for homeowners.