What this calculator does

Standard deviation measures how spread out values are around the mean. Enter a list of numbers to calculate the mean, variance and standard deviation.

Formula used

The calculator finds the mean, squares each distance from the mean, averages those squared distances, then takes the square root. Sample mode divides by n minus 1.

How to read the result

A higher standard deviation means the values are more spread out. Sample mode is normally used when the values are a sample from a larger group.

Assumptions

  • Accepts comma or space separated numbers.
  • Sample standard deviation needs at least two values.
  • Does not remove outliers automatically.

Sources and checks

This calculator uses a standard public formula. Where rules or thresholds can change, source links are listed on the relevant page.

Frequently asked questions

Should I use sample or population?

Use population if your list contains every value in the group. Use sample if your list is only a subset used to estimate the wider group.