Standard Deviation Calculator
Calculate the standard deviation, variance, and mean of any set of numbers.
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Enter your values and the result appears here
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About this calculator
Standard deviation tells you how spread out your data is — whether the numbers cluster around the average or scatter widely. It is one of the most important concepts in statistics. Our standard deviation calculator handles the math for any set of numbers you enter. Just type or paste comma-separated values and get the full statistical summary.
The formula, explained simply
We calculate the mean (average) of your numbers, then find the difference between each number and the mean, square those differences, average them (that is the variance), and take the square root to get the standard deviation. We also show the count of numbers, minimum, maximum, and range. The calculator uses the population standard deviation formula (dividing by n) rather than the sample formula (dividing by n-1).
When you would use this
Students complete statistics assignments and exam prep. Researchers analyze survey or experimental data. Quality control teams measure consistency in manufacturing. Investors assess the volatility of stock returns. Data analysts get a quick statistical snapshot of any dataset.