Standard Deviation Calculator
Paste in a list of numbers to instantly get the mean, variance, and both sample and population standard deviation.
Count
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Sum
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Mean
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Variance
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Std. Deviation
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Range
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Standard Deviation Formulas
Standard deviation measures how spread out a set of numbers is from their average. A small value means the numbers are clustered tightly around the mean; a large value means they’re spread widely.
Population is used when your data represents an entire group. Sample is used when your data is a subset used to estimate a larger population, it divides by n−1 instead of n to correct for that uncertainty.
How to Use This Standard Deviation Calculator
Paste or type your numbers into the box, commas, spaces, and line breaks are all accepted.
Choose Sample or Population, depending on whether your data is a subset or the full data set.
Results update instantly, including count, sum, mean, variance, and standard deviation.
Frequently Asked Questions
Should I use sample or population standard deviation?
Use population standard deviation when your numbers represent the entire group you care about. Use sample standard deviation when your numbers are only a subset used to estimate a larger population, this is the more common case in surveys and experiments.
What is variance, and how is it related to standard deviation?
Variance is the average of the squared differences from the mean. Standard deviation is simply the square root of variance, which brings the value back into the same units as your original data.
Does the order of the numbers matter?
No, standard deviation only depends on the values themselves, not the order they’re entered in.
Can I paste data directly from Excel or Google Sheets?
Yes, copy a column or row of numbers and paste it into the box. Line breaks, tabs, and spaces are all recognized as separators.