Free Tool

Standard Deviation Calculator

Calculate standard deviation, variance, and mean for your data set. Free statistical tool with step-by-step calculations and explanations.

Enter Your Data

Enter comma-separated numbers to calculate standard deviation, variance, mean, and more.

Enter numbers separated by commas, spaces, or new lines
Use sample for data from a subset, population for complete data

Your Statistical Results

Standard Deviation
-
Spread of data
Variance
-
σ² or s²
Mean
-
Average (μ or x̄)
Count (n)
-
Number of values
Sum
-
Σx
Sum of Squares
-
Σ(x-μ)²

Download Statistics Formula Cheat Sheet

Get our free PDF with all statistical formulas, standard deviation examples, and calculation steps.

How to Calculate Standard Deviation

Standard deviation measures how spread out numbers are from the mean. Our calculator handles both sample and population standard deviation.

Standard Deviation FAQ

What is the difference between sample and population standard deviation?

Sample standard deviation uses n-1 in the denominator (Bessel's correction) to estimate population parameters. Population standard deviation uses N. Use sample when your data is a subset of a larger population.