Standard Deviation Calculator
Calculate population or sample standard deviation and variance from a list of values.
Start with your input
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Choose your options
These settings are optional. Keep the defaults to get started.
How to use Standard Deviation Calculator
- Enter the measurements or amounts in the fields above.
- Check that dimensions, rates and units match the labels.
- Select “Calculate standard deviation” to see a clear estimate and the formula used.
How the standard deviation calculator works
Population variance divides squared deviations by N; sample variance divides by N − 1. Standard deviation is the square root of variance.
Check your measurements and assumptions
Use population mode when the values are the complete group of interest; use sample mode when they represent a sample used to estimate a larger group.
Review the estimate before you act
Compare this result with an independent measurement, supplier quote or institution guidance when the decision matters. Confirm that the units and assumptions match the labels above, and update the inputs when the conditions change. Keep a note of the values used so you can reproduce the estimate later. This calculator is a planning aid and does not replace professional, product-specific or local guidance.
When should I use sample standard deviation?
Use the sample formula with N − 1 when your values are a sample and you are estimating variation in a larger population.
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