Standard Deviation Calculator
Population and sample standard deviation, variance and mean.
Standard deviation (sample)
5.237229
Variance
27.428571
Mean
18
Count
8
Other type
4.898979
ShowHide the working
- 1Mean = 18
- 2Sum of squared deviations ÷ (N − 1) = variance = 27.428571
- 3√variance = 5.237229
Formula
σ = √(Σ(x − μ)² ÷ N), s = √(Σ(x − x̄)² ÷ (N − 1))How it works
Standard deviation measures spread around the mean. Divide by N for a whole population, by N−1 for a sample.
Example
For that eight-value set the sample standard deviation is about 5.24.
More in Statistics
- Statistics Calculator
- Standard Deviation Calculator
- Mean, Median & Mode
- Weighted Average Calculator
- Z-Score Calculator
- Confidence Interval Calculator
- Probability Calculator
- Binomial Distribution Calculator
- Normal Distribution Calculator
- Correlation Calculator
- Linear Regression Calculator
- Percentile Calculator
- Sample Size Calculator
About the Standard Deviation Calculator
Population and sample standard deviation, variance and mean. It sits in the Statistics section of NWS Calc, a free collection of calculators that run entirely in your browser. There is no signup, no paywall and no tracking — open the page, enter your numbers, get an answer.
Frequently asked questions
- Is the Standard Deviation Calculator free to use?
- Yes. Every calculator on NWS Calc is completely free, with no signup, no usage limits and no ads.
- Does my data leave my device?
- No. The Standard Deviation Calculator runs entirely in your browser using JavaScript. Nothing you type is uploaded, logged or stored on a server.
- Can I use the Standard Deviation Calculator on my phone?
- Yes. The page is fully responsive and works in any modern mobile or desktop browser — there is nothing to install.
- What else is in Statistics?
- Mean, deviation, regression, probability and distributions. You can browse the full Statistics category for related calculators.