Standard Deviation Calculator
About Standard Deviation Calculator
The Standard Deviation Calculator helps you find how spread out a set of data values is from the mean. It’s a quick and accurate tool for students, researchers, and professionals working with data analysis, probability, and statistics.
Standard Deviation Formula›
Population SD (σ) = √[ Σ(x − μ)² / N ] Sample SD (s) = √[ Σ(x − x̄)² / (n − 1) ]
Where: x = each value, μ or x̄ = mean of the dataset, N = total number of items (population), n = sample size. The calculator automatically determines standard deviation depending on your input selection.
Example:
Input: Data: 4, 8, 6, 5, 3
Output: Mean = 5.2, Standard Deviation ≈ 1.72
Steps to Use:
- Enter your data values separated by commas or spaces.
- Choose whether the data represents a sample or a population.
- Click 'Calculate' to find the mean and standard deviation.
- Review results including variance and data spread.
Frequently Asked Questions
What is Standard Deviation?›
Standard deviation measures how spread out numbers are in a dataset. A low SD means values are close to the mean, while a high SD means values are more spread out.
What is the difference between population and sample standard deviation?›
Population SD uses N (total items), while sample SD uses n−1 to account for smaller sample sizes. Use population SD for entire datasets and sample SD when working with a subset.
Why is standard deviation important?›
It helps measure data variability and consistency — widely used in research, finance, quality control, and predictive modeling.
Can I enter both decimals and negative numbers?›
Yes, the calculator supports all real numbers including decimals and negatives for accurate computation.
Does this calculator also show variance?›
Yes. Along with standard deviation, it can display mean, variance, and data count for a complete statistical overview.