How to use this calculator
Standard deviation measures spread in the same units as the data.
The method
Standard deviation = √variance
Enter your values in the labeled fields and choose Calculate. The result panel shows the answer and supporting values when useful.
WORKED EXAMPLE INPUT
Numbers: 4, 7, 9, 10, 12, Standard deviation type: sample
Select Calculate to evaluate these example values.
Scope and limitations
At least two values are required for sample standard deviation.
Common questions
Can I use different units?
Use consistent units unless this page is a unit converter. The result follows the units implied by the inputs.
Are results exact?
Displayed values may be rounded. Keep extra precision for important follow-up calculations.
Methods & verification
Formulas use standard mathematical definitions and fixed unit factors where applicable. See our methodology for numerical conventions, rounding, privacy, and limitations.