Standard Deviation Calculator
Calculate mean, variance and standard deviation.
About this tool
Standard deviation measures how spread out a set of numbers is from the mean. This calculates the mean, variance and standard deviation — both the population version (when your numbers are the entire data set) and the sample version (when they're a sample used to estimate a larger population).
Key Features
- Mean and variance
- Population standard deviation
- Sample standard deviation (Bessel's correction)
How to Use
- Paste or type your numbers, separated by commas, spaces or new lines.
- Click Calculate.
Benefits
- Understand data spread at a glance
- Correctly distinguish population vs. sample statistics
- Quick check without spreadsheet formulas
Frequently Asked Questions
Use population standard deviation when your numbers are the entire group you care about. Use sample standard deviation when your numbers are a sample drawn from a larger population you're trying to estimate \u2014 it divides by (n\u22121) instead of n, which corrects for the sample tending to underestimate spread.
The sample formula divides by (n\u22121), which is undefined for a single data point \u2014 with only 1 value entered, only the population version (which is 0, with no spread) can be shown.