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Standard Deviation Calculator — Mean, Median, Variance

Paste a list of numbers — from a spreadsheet, separated by commas, spaces or new lines — and get the standard deviation (sample and population), variance, mean, median, mode, range and quartiles, with the steps.

Runs in your browserUpdated
Separate with commas, spaces, tabs or new lines. Paste a column from Excel or Google Sheets.
Sample standard deviation (s)
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    Your data never leaves your computer. All processing happens 100% locally in your browser.

    How to use the Standard Deviation Calculator

    1. Paste or type your numbers.
    2. Read the sample standard deviation (for data that’s a sample of a larger group) or the population one (when you have every value).
    3. See the mean, median, mode, range, quartiles and the steps.

    What standard deviation tells you

    Standard deviation measures how spread out numbers are around their average. A small value means most numbers are close to the mean; a large one means they’re widely spread. In a roughly normal distribution about 68% of values fall within one standard deviation of the mean, and 95% within two.

    Sample vs population

    If your numbers are every member of the group (all 30 students in a class), use the population standard deviation σ, which divides by n. If they’re a sample of a bigger group (30 customers out of thousands), use the sample standard deviation s, which divides by n − 1 to correct for the sample’s bias.

    s = √( Σ(x − x̄)² ÷ (n − 1) )

    Quartiles use the same method as Excel’s QUARTILE.INC. Need a quick average of grades? Try the GPA Calculator; for other maths, the Scientific Calculator.

    Also searched as: variance calculator, mean median mode calculator, statistics calculator, sample standard deviation, population standard deviation, quartile calculator, average calculator.

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    Frequently asked questions

    Should I use sample or population standard deviation?
    Use population (σ) when your data includes every member of the group, and sample (s) when it’s a subset used to estimate a larger group. Sample is the usual choice in research and surveys.
    How do I calculate standard deviation by hand?
    Find the mean, subtract it from each number and square the results, average those squares (dividing by n − 1 for a sample), then take the square root. The steps are shown with your numbers.
    Can I paste from Excel?
    Yes. Copy a column or row of cells and paste it; numbers separated by tabs, commas, spaces or new lines are all read.
    Can I install Standard Deviation Calculator as a web app and use it offline?
    Yes. Standard Deviation Calculator is an installable web app (PWA) — installed from your browser, not downloaded from an app store. Click Install app at the top of this page in Chrome or Edge (Windows, macOS, Linux, ChromeOS) or on Android, use Share → Add to Home Screen on iPhone and iPad, or File → Add to Dock in Safari 17+ on a Mac. It then opens in its own window with its own icon, and because it runs entirely in your browser it keeps working offline. Firefox on desktop can’t install web apps. How installing works.

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