Math & Scientific
Variance Calculator
Variance: it computes the variance = Σ(x − mean)² ÷ n for a population, or ÷ (n − 1) for a sample. Worked through below with real figures, and the calculator repeats the working on your own inputs — free, on-device, instant.
Variance Calculator is a browser-based way to work out the variance. Feed it your numbers and it computes the variance and mean on the spot, keeping your data local.
About this calculator
Variance is easiest to get wrong in the setup, not the arithmetic. It computes the variance = Σ(x − mean)² ÷ n for a population, or ÷ (n − 1) for a sample. It matters when you need the exact relationship checked quickly rather than worked through by hand. The worked example on this page (For 2, 4, 6, 8 (population): mean = 5, variance = (9+1+1+9) ÷ 4 = 5 .) shows the full substitution; the calculator above runs the same working on your own numbers, in your browser, with nothing uploaded.
How to use
- Type the numbers in your data set, separated by commas or spaces.
- Press Calculate to compute the variance.
- Read the sample and population variances.
- Press Reset and try another data set.
Why use Variance Calculator
Fast
Calculations run in your browser. No round trip to a server.
Private
Your inputs never leave your device. Nothing is uploaded.
Free
No signup, no paywall, no ads-in-results, no watermarks.
Accurate
Uses standard, well-established formulas; check critical results independently.
Mobile-ready
Optimised for phones, tablets, and desktops alike.
Transparent
Honest disclaimers wherever browser limits or regional rules apply.
Common uses
Use it when working through problems
Use it for quick mental-math cross-checks
Use it when revising for exams
Use it when comparing two different methods
Variance in competitive-exam practice
Variance in tutoring and teaching sessions
Technical notes
Variance Calculator computes the variance = Σ(x − mean)² ÷ n for a population, or ÷ (n − 1) for a sample.
Inputs are taken exactly as entered, so check for typos before trusting an answer.
Results are rounded for display; the underlying calculation keeps full precision.
FAQ
What is the difference between sample and population variance?
Sample variance divides the squared deviations by n - 1; population variance divides by n. Use sample variance when your data is a sample of a larger group.
How does variance relate to standard deviation?
The standard deviation is the square root of the variance, so this tool also shows both standard deviations for convenience.
Why are at least two numbers required?
Sample variance divides by n - 1, so it cannot be computed from a single value.
Does the Variance Calculator send my data to a server?
No. The Variance Calculator runs entirely in your browser, so nothing you enter is uploaded, stored, or shared.
Worked example
For 2, 4, 6, 8 (population): mean = 5, variance = (9+1+1+9) ÷ 4 = 5.