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Category: Calculators

Standard Deviation Calculator

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Find sample and population standard deviation from a list of numbers

Calculate sample and population standard deviation, variance, mean, sum, min and max from pasted numbers, locally in your browser.

Separate values with commas, spaces, semicolons or line breaks.

Sample standard deviation (s)2.13809
Count8Sum40Average (mean)5Minimum2Maximum9Range7Sample standard deviation (s)2.13809Sample variance (s²)4.571429Population standard deviation (σ)2Population variance (σ²)4
Result
Count: 8
Sum: 40
Average (mean): 5
Minimum: 2
Maximum: 9
Sample standard deviation (s): 2.13809
Sample variance (s²): 4.571429
Population standard deviation (σ): 2
Population variance (σ²): 4

How each one is calculated

  • Sample: divide the summed squared deviations by n − 1. Use it when your numbers are part of a larger group.
  • Population: divide by n. Use it when your numbers are the entire group you care about.

Everything is calculated on this device; the numbers are never uploaded.

Everything on this page is processed in your browser. Nothing is uploaded.

What this tool does

Paste a list of values in whatever shape you have them — comma-separated from a spreadsheet, space-separated from a log, or one per line — and this returns the descriptive statistics that usually get asked for together: count, sum, mean, minimum, maximum, range, and both forms of variance and standard deviation. Both forms are shown at once on purpose. The sample figure divides by n − 1 and the population figure by n, and which one is correct depends entirely on whether your numbers are the whole group or a piece of a bigger one. Showing only one would silently make that choice for you.

How to use it

  1. Paste or type your numbers, separated by commas, spaces, semicolons or line breaks.
  2. Choose sample or population for the headline figure.
  3. Read the full set of statistics below it, and copy the summary if you need it.

Privacy

This tool runs entirely in your browser. Your input is never uploaded, stored or shared — closing the tab removes it.

Frequently asked questions

What is the difference between sample and population standard deviation?
The divisor. Population divides the summed squared deviations by n and describes a group you have measured completely. Sample divides by n − 1 — Bessel's correction — and estimates the spread of a larger group from a subset of it.
Which one should I use?
Population when your numbers are the entire group you care about, such as the marks of every student in one class. Sample when they stand in for something bigger, such as 40 response times drawn from a service that handles millions.
Which separators can I use?
Commas, spaces, tabs, semicolons, pipes and line breaks all work, so you can paste straight from a spreadsheet column or a log line. Note that this makes 1,234 two values rather than one thousand two hundred and thirty-four.
Does it show variance too?
Yes, in both forms: sample variance (s²) and population variance (σ²), alongside their square roots.
Are my numbers uploaded?
No. They are parsed and calculated in your browser, and anything that is not a number is listed as ignored rather than silently counted as zero.

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