Standard Deviation Calculator
Calculate the sample and population standard deviation, variance, and mean for a set of numbers.
Runs in your browser Your input never leaves your device.
About this tool
Paste a list of numbers separated by commas, semicolons, spaces or new lines and see the count, mean, population standard deviation (σ), sample standard deviation (s) and population variance. Population standard deviation divides the squared differences from the mean by N; sample standard deviation divides by N-1, which is the usual choice when your numbers are a sample of a larger group. At least two numbers are needed. Results are rounded to four decimal places. Leading, trailing or doubled separators are ignored, and entries that are not numbers are silently dropped, so check the count shown matches what you expected. All calculation happens in your browser.
How to use it
- Enter your numbers, separated by commas, semicolons or spaces.
- Check the count matches how many numbers you entered.
- Use the sample value for a sample, or the population value if you have every data point.
Example
The squared differences sum to 910: 910/6 = 151.67 and 910/5 = 182.
4, 8, 15, 16, 23, 42
Count: 6 Mean: 18 Population std dev (σ): 12.3153 Sample std dev (s): 13.4907 Variance (population): 151.6667
Common problems
- A value I typed was ignored or split
- Text entries are dropped. A decimal comma is read as a separator, so 1,5 becomes the two numbers 1 and 5. Use a decimal point.
- Nothing is shown
- Fewer than two valid numbers gives no result. Check the count after adding more values.
- Which one should I use?
- Use the sample value when your data is a sample from a bigger population, and the population value when it covers everyone.