Guides & calculators
Everything you need to understand variance, from the first definition to checking a spreadsheet formula. New to the topic? Start withWhat is variance?
Learn
- 01What Is Variance?What variance measures, how to read it, and where it shows up in grades, investing and quality control.
- 02How to Calculate VarianceThe five-step method by hand, with a fully worked example and the mistakes to avoid.
- 03The Variance Formula ExplainedEvery symbol in σ² and s², the shortcut formula, and the formula for grouped (frequency) data.
- 04Sample vs Population VarianceWhen to divide by n − 1, a small proof that it works, and a checklist for picking the right one.
- 05Variance in Excel, Google Sheets, Python and RWhich function to use (VAR.S, VAR.P, statistics.variance, var) and the defaults that catch people out.
Calculators
- Variance CalculatorSample and population variance, standard deviation, mean and sum of squares, with every step shown.
- Standard Deviation CalculatorSample and population standard deviation, how it relates to variance, and how to interpret it.
- Percent Variance CalculatorVariance between two numbers, such as budget vs actual, as an amount and a percentage.