Standard Deviation Calculator
Compute standard deviation and variance using the population or the sample (n−1) formula for any list of numbers.
Example values are shown — change any of them and the answer updates live.
Standard deviation
σ 2
Population · n=8
A Population standard deviation of σ means roughly Within ±1σ of values fall inside one σ of the mean.
Mean5
Variance4
Within ±1σ3 – 7
Within ±2σ1 – 9
Coefficient of variation40%
How deviation is computed
Step 1 · Distance from the mean
x̄ = Σx ÷ n
40 ÷ 8
5
Step 2 · Average of squared distances
σ² = Σ(x−x̄)² ÷ n
÷ 8
σ 2
Exact arithmetic — computed instantly in your browser.