STATISTICS

Standard deviation calculator

Measure sample dispersion around the mean.

01 / INPUTS

Your numbers

02 / YOUR RESULT
2.138
Sample standard deviation

Mean: 5

Default inputs are examples. Change them to match your situation.

How to use this calculator

Measure sample dispersion around the mean. Enter values (comma or space separated). The result updates when you change an input. To compare two sets of inputs, save scenario A, then enter the second set; the result panel shows the difference.

Formula and limits

Sample standard deviation = √[Σ(x−mean)²/(n−1)]. Requires at least two values. Uses the sample, not population, denominator.

Worked example

The following example uses the calculator’s starting values. It is an illustration of the method, not a recommended target.

InputExample value
Values (comma or space separated)2, 4, 4, 4, 5, 5, 7, 9

Sample standard deviation: 2.138
Mean: 5

Interpreting your result

Check whether your values represent a sample or an entire population. The sample-variance tools use n−1 in the denominator. Descriptive summaries cannot establish causation or validate how a sample was collected.

Comparing alternatives

Save the first result as scenario A, then change one input. The comparison shows the numeric difference; it does not label either result as better. Choose inputs that describe realistic alternatives. Values shown on screen are rounded, so calculations from rounded intermediate results may differ slightly.

Background reading

OpenStax Introductory Statistics. This is a subject reference, not an endorsement or independent review of Calcaven.

Implementation updated September 25, 2026 · How we check calculations