Standard Deviation Calculator
Find the standard deviation, variance and mean of a data set, for either a sample or a whole population.
Separate values with commas, spaces or new lines.
Enter at least two numbers for a sample standard deviation.
Enter your numbers separated by commas, spaces or new lines. Choose whether they're a sample (part of a larger group) or the whole population — this changes how the spread is calculated.
Frequently asked questions
Population standard deviation divides by n and is used when your data covers the whole group. Sample standard deviation divides by (n − 1) and is used when your data is a sample of a larger group — the smaller denominator corrects a bias, giving a better estimate of the true spread.
It measures how spread out the numbers are around the mean. A small standard deviation means values cluster close to the average; a large one means they're widely scattered.