# Standard Deviation Calculator – Variance & SD

> Use this sd calculator to compute sample and population standard deviation, variance, mean, and count from a list of numbers.

**URL:** https://www.calculatoranswers.com/standard-deviation-calculator
**Category:** Education

## Quick Answer

Compute the sample or population standard deviation for a set of numbers. Choose which one you need, then read the standard deviation alongside the variance, mean, and count.

## Definition

A standard deviation calculator quantifies how far the values in a dataset typically sit from their mean, in the same units as the data. It computes the population standard deviation, which applies when the values are the entire group, and the sample standard deviation, which estimates variability from a subset and divides by n - 1 under Bessel's correction. Statisticians, researchers, and quality control analysts use it to judge consistency and spread.

## How to Use

1. **Choose sample or population** — Select Sample if your numbers are a subset drawn from a larger group, or Population if they are the entire group. The choice changes the denominator and is shown in the result.
2. **Enter your data** — Type or paste your numbers into the text area, separated by commas, spaces, semicolons, or line breaks. Any entry that does not read as a number is named and blocks the calculation until it is corrected.
3. **Read the standard deviation** — The standard deviation appears first, with the variance, mean, count, and sum of squared deviations beneath it, plus the formula and the substituted calculation.

## Disclaimer

This calculator provides estimates for educational and planning purposes. Always consult a qualified professional for specific advice on financial, medical, legal, or other regulated decisions.

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