Standard Deviation Calculator
Calculate standard deviation to describe the spread of values around the mean. It is useful for study, lab preparation, engineering notes, or checking a calculation where consistent units matter.
How to use this calculator
Enter the dataset or summary values required by the calculator. Make sure the values belong to the same sample and that you know whether the tool uses population or sample statistics when that distinction applies.
Formula
Standard deviation = โvariance; population and sample versions use their corresponding variance.
Quick check
Use the calculator as a quick verification tool as well as a way to get the final number. Understanding what the result represents is just as important as the number itself. For technical or academic work, write down the units alongside the numbers. A mathematically correct calculation can still be misleading if the units are wrong.