Standard Deviation Calculator
Find the sample or population standard deviation and variance of a list of numbers.
What is standard deviation?
Standard deviation measures how spread out values are around the mean. A low value means the numbers sit close to the average; a high value means they're spread widely. Two classes can have the same average score, yet the one with the higher standard deviation has more uneven results.
Sample vs population
- Sample standard deviation (n − 1): your data is part of a larger group (a survey, an experiment)
- Population standard deviation (n): your list contains the whole group
The calculator shows the mean, variance and standard deviation together.
Use cases
Statistics homework, quality control, financial volatility and evaluating experimental results. Calculation happens in your browser.
How to use Standard Deviation Calculator
- Paste your numbers.
- Choose the sample or population formula.
- Review the mean, variance and standard deviation.
- Copy the results.
Why use this tool?
Removes the risk of mistakes from applying statistics formulas by hand.
FAQ
Should I choose sample or population?
Use sample for survey or experiment data drawn from a larger group; use population if the list contains the whole group.
How are variance and standard deviation related?
Standard deviation is the square root of variance and has the same unit as the data.
Which Excel function matches?
STDEV.S is the sample and STDEV.P the population standard deviation.
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