TopToolAIStandard Deviation Calculator
ⓘ About this tool
🔄 Last updated 21 Sep 2026
✓ Reviewed by TopToolAI Team
Paste in a list of numbers and get the standard deviation (both population and sample), the variance, mean, median, mode and range. A small table shows the working for each value.
How to use Standard Deviation Calculator
Step-by-step guide to the boxes below. Open it only if you need help.
How to use Standard Deviation Calculator
Step-by-step guide to the boxes below. Open it only if you need help.
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1
Numbers Text box
Separate the numbers with commas, spaces or new lines.
Example: 2, 4, 4, 4, 5, 5, 7, 9
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2
Press “Calculate”
Click the button under the boxes. If something is missing or not valid, a short message tells you which box to fix.
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3
Read your result
Your answer appears under the button, with a short note in plain words where it helps. Change any box and press again to compare different numbers.
Standard Deviation Calculator FAQs
Sample or population: which one do I use?
If your numbers are only a sample of a bigger group, use the sample standard deviation (it divides by n − 1). If they are the whole group, use the population one (it divides by n).
What does a big standard deviation mean?
The values are spread out a long way from the average. A small one means they are bunched close together.
How do I calculate standard deviation by hand?
Find the mean, square each difference from the mean, average those squares and take the square root. For a sample, divide by n − 1.
What is the difference between variance and standard deviation?
Variance is the average squared deviation. Standard deviation is its square root, in the same units as your data.
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