Standard Deviation Calculator
Enter a dataset to calculate mean, median, mode, variance, standard deviation, and more. Supports population and sample formulas.
Enter numbers separated by commas or spaces
Formula:
Std Deviation
Mean (Average)
Variance
Median
Mode
Range
Count (n)
Min
Max
Frequently asked questions
What is the difference between sample and population standard deviation?
Population std dev (σ) divides by n and is used when you have data for the entire population. Sample std dev (s) divides by n−1 and is used when your data is a sample from a larger population. The n−1 correction (Bessel's correction) makes the sample estimate less biased.
What is a standard deviation?
Standard deviation measures how spread out values are from the mean. A low std dev means values are clustered close to the average; a high std dev means values are spread over a wider range.
What counts as an outlier?
This calculator highlights values more than 2 standard deviations from the mean as potential outliers. In a normal distribution, about 95% of values fall within 2σ of the mean.
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