Standard Deviation Calculator

This Standard Deviation Calculator helps you measure how spread out a set of numbers is. It calculates both population and sample standard deviation instantly.

Enter Numbers (comma separated)

Enter values separated by commas. Decimals are supported.

Results

Mean

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Population SD

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Sample SD

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What Is Standard Deviation?

Standard deviation is a statistical measure that shows how much the values in a data set differ from the mean. A low standard deviation means values are close to the mean, while a high standard deviation indicates greater variability.

Population vs Sample Standard Deviation

Population Standard Deviation: Used when the data set includes the entire population.
Sample Standard Deviation: Used when the data set is a sample of a larger population.

Standard Deviation Formulas

Population SD:
σ = √[ Σ(x − μ)² / N ]
Sample SD:
s = √[ Σ(x − x̄)² / (n − 1) ]

Frequently Asked Questions

A high standard deviation means the data values are spread out over a wider range.

Use sample standard deviation when your data represents only part of a larger population.

Yes. Both whole numbers and decimals are supported.