Standard Deviation Calculator
Mean, variance, and standard deviation of a data set.
How it works
Population SD = √(Σ(x − mean)² ÷ n). Sample SD divides by n − 1 instead.
FAQ
Is this calculator free?
Yes. No signup is needed and nothing you enter is stored.
Is the result exact?
Results are rounded for display. For financial, medical, or legal decisions, confirm with a professional.
Do my numbers leave my device?
No. The calculation runs in your browser.