Standard Deviation & Statistics Calculator
Standard deviation calculator: paste your data to get sample and population standard deviation, variance, mean, median, mode and quartiles.
s = √Σ(xi − x̄)²n − 1
How to use this calculator
- Type your input in the box.
- The result updates as you type.
- Use “Copy result” or “Copy link” to share it.
The standard deviation measures how spread out data are around the mean. Use the sample formula s (dividing by n − 1) when your data are a sample, and the population formula σ (dividing by n) when they are the whole population.
Paste numbers separated by spaces, line breaks or semicolons (commas also work in the English version). The tool returns all the usual descriptive statistics at once.
Worked example
Data 2, 4, 4, 4, 5, 5, 7, 9: mean 5, population σ = 2, sample s = 2.138, median 4.5, mode 4.
Frequently asked questions
Should I use sample or population standard deviation?
Sample (n − 1) in almost all lab and survey work, because you are estimating the spread of a larger population from a sample.
How are quartiles calculated?
By linear interpolation between ordered values (the same method as Excel’s QUARTILE.INC).