Standard Deviation Calculator
Enter numbers separated by commas, spaces or new lines to see the full descriptive statistics of your data set.
- Count (n)
- 6
- Sum
- 108
- Mean
- 18
- Median
- 15.5
- Mode
- none
- Minimum
- 4
- Maximum
- 42
- Range
- 38
- First quartile (Q1)
- 9.75
- Third quartile (Q3)
- 21.25
- Population variance (σ²)
- 151.666667
- Sample variance (s²)
- 182
- Standard error of the mean
- 5.507571
- Coefficient of variation
- 74.95%
About this tool
Standard deviation measures how spread out values are around the mean. The sample formula (dividing by n − 1) is the one to use when your numbers are a sample of a larger population, which is nearly always the case in surveys, experiments and quality checks; the population formula (dividing by n) applies when you have every value. Both are shown, with the variances they are the square roots of.
The calculator also reports median and quartiles, which are robust to outliers, the mode, the range, the standard error of the mean and the coefficient of variation for comparing spread between data sets with different units. Paste directly from a spreadsheet column.
Frequently asked questions
- Sample or population — which should I report?
- Sample, unless your data covers the entire group you are describing.
- How are quartiles computed?
- By linear interpolation between sorted values (the method used by Excel's QUARTILE.INC and NumPy's default).
- Can I paste numbers with decimal commas?
- Yes, if they are separated by spaces or new lines. Comma-separated lists are read as separate numbers.