Standard Deviation Calculator

Calculate standard deviation, variance, and other statistics for a data set.

Value 1

Value 2

Value 3

Value 4

Value 5

Results

Standard Deviation (σ)7.07

Variance (σ²)50

Mean20

Range20

Ad — 300×250

What is Standard Deviation?

Standard deviation measures how spread out numbers are from their average (mean). A low standard deviation means data points are close to the mean; a high standard deviation means they are spread out.

It's the most widely used measure of variability in statistics, used in finance (stock volatility), quality control, science, and data analysis.

Formula

σ = √[Σ(xi − μ)² / N]

Where: - σ = Population standard deviation - xi = Each value - μ = Mean - N = Number of values

Variance = σ²

How to use this Standard Deviation Calculator?

1. Enter up to 5 values. 2. See standard deviation, variance, mean, and range. 3. Lower SD = more consistent data.

Frequently asked questions

What is the difference between population and sample SD?

Population SD divides by N. Sample SD divides by N-1 (Bessel's correction). Use sample SD when your data is a subset of a larger population.

What does a high standard deviation mean?

High SD means values are widely spread from the mean. In investing, high SD means high volatility/risk.

What is the 68-95-99.7 rule?

In a normal distribution: 68% of data falls within 1 SD, 95% within 2 SD, and 99.7% within 3 SD of the mean.

Ad — 728×90