Standard Deviation Calculator
Calculate the standard deviation, variance, mean, and sum of squares for a set of numbers. Useful for statistics, data analysis, and quality control.
Published by:
isCalculator Editorial Team
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How to use this tool?
How to Use the Standard Deviation Calculator
- Enter your data in the text area as comma-separated numbers (e.g.,
5, 10, 15, 20, 25). Decimals are allowed. - Select the type:
- Sample – use when your data is a subset of a larger group (requires at least 2 numbers).
- Population – use when your data includes every member of the group.
- Click Calculate to see:
- Standard Deviation – spread of data around the mean.
- Variance – squared standard deviation.
- Mean – average of your numbers.
- A Formula Breakdown shows each calculation step for learning.
Tip: Use commas only to separate numbers. Leave empty fields or non-numeric characters will show an error.
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Frequently Asked Questions
Standard deviation measures the amount of variation or dispersion in a set of values. A low standard deviation indicates that values tend to be close to the mean, while a high standard deviation indicates that values are spread out over a wider range.
Sample standard deviation is used when data represents a sample from a larger population (divides by n-1), while population standard deviation is used when data includes the entire population (divides by n). The sample formula corrects for bias.
Enter numbers separated by commas (e.g., 5, 10, 15, 20). You can also include decimals. The calculator will automatically parse the input and compute the statistics.
