Standard Deviation Calculator
Compare sample and population standard deviation, variance and mean, with a distribution chart and local CSV import.
How to use this calculator
Paste numbers separated by spaces, commas or semicolons. Use a decimal point and no thousands separators. For CSV or TSV files, choose a numeric column and indicate whether the first row contains column names. Files stay in your browser.
Calculation method
Calculate the mean, then the sum of squared differences from that mean. Population variance divides by n; sample variance divides by n − 1. Standard deviation is the square root of variance.
Worked example
For 2, 4, 4, 4, 5, 5, 7, 9 the mean is 5 and the squared-deviation sum is 32. Population standard deviation is 2; sample standard deviation is approximately 2.13809.
Save and share your result
Calculate after changing inputs. Print report prepares a clean printable view, and Download CSV saves the result. Copy link shares the tool; enable Include inputs only when you want those values visible to anyone with the link. Reset restores the example.
Standard Deviation Calculator FAQs
Should I choose sample or population?
Use population when the data are the entire group you want to describe. Use sample when estimating variation in a larger group from observations. Both are shown for comparison.
What happens to empty CSV cells?
Empty cells in the selected column are skipped. Other nonnumeric cells cause an error; enable the header option when the first row contains names.