Standard Deviation Calculator
Separate values with commas, spaces or new lines.
Enter at least one number to see the results.
- Count (n)
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- Sum
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- Mean (average)
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- Minimum
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- Maximum
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- Range
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What is Standard Deviation Calculator
Standard deviation measures how spread out a set of numbers is around its mean. A low value means the data points sit close to the average; a high value means they are scattered widely. This calculator reads your list of numbers and returns both the sample standard deviation (dividing by n minus 1) and the population standard deviation (dividing by n), along with the variance, mean, sum, minimum, maximum and range.
How to use
- Type or paste your numbers into the box.
- Separate the values with commas, spaces or new lines.
- Read the sample and population standard deviation at the top.
- Check the variance, mean, count, sum and range below.
When to use it
Got a set of exam scores like 2, 4, 4, 4, 5, 5, 7, 9 and want to know how consistent they are? Paste them in and you get a mean of 5, a population standard deviation of 2 and a sample standard deviation of about 2.14. Use the sample figure when your data is a subset drawn from a larger group, and the population figure when the numbers cover the entire group you care about.
Frequently asked questions
What is the difference between sample and population standard deviation?
Sample standard deviation divides the sum of squared deviations by n minus 1 (Bessel’s correction) and is used when your data is a sample from a larger population. Population standard deviation divides by n and is used when your data covers the whole group. This tool shows both.
How is standard deviation calculated?
Find the mean, subtract it from each value and square the result, add those squared differences, divide by n (population) or n minus 1 (sample) to get the variance, then take the square root.
What number format can I paste?
Any list separated by commas, spaces, semicolons or new lines. Decimals and negative numbers are supported, and non-numeric text is ignored.
Can I share this tool with my numbers pre-filled?
Yes. The URL updates automatically as you type. Copy it from the address bar or use the Share button, and anyone who opens the link will see your exact numbers ready to go.
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