Standard Deviation Calculator
Sample and population SD
Use this when you need a fast, accurate result — no sign-up, works entirely in your browser.
Sample SD—
Population SD—
How to Use
- Enter your details into the fields above.
- Click the calculate button to get your result instantly.
- Use the clear button to start a new calculation.
Example
- 2, 4, 4, 6, 8 → Sample SD 2.2804, population SD 2.0396
- 10, 12, 23, 23, 16 → Sample SD 6.0581, population SD 5.4185
Formula
Population SD = √(Σ(x − μ)² / N). Sample SD = √(Σ(x − x̄)² / (n − 1)). Use the sample figure when your numbers are only a subset of a larger group — dividing by n − 1 (Bessel’s correction) removes the downward bias of small samples.
About Standard Deviation Calculator
Sample and population SD. This free online tool gives you fast, accurate results without registration or downloads.
Everything runs locally in your browser, so your data is never uploaded or stored — privacy first.
Frequently Asked Questions
Is the Standard Deviation Calculator accurate? +
Yes, the Standard Deviation Calculator gives precise results using standard mathematical formulas, with no rounding errors in typical use.
Is the Standard Deviation Calculator free to use? +
Yes, it is completely free with no registration or download required.
Does the Standard Deviation Calculator work on mobile? +
Yes, it works on any device with instant, in-browser results.