Standard Deviation Calculator
Compute population and sample standard deviation with variance, mean, median, and range for any dataset — exam scores, lab readings, quality checks. A class scoring 70±8 reads spread at a glance — free, runs locally.
How to Use the Standard Deviation Calculator
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Frequently Asked Questions
What does standard deviation tell me?
Spread around the mean: scores 70±8 cluster tightly, 70±20 scatter widely. Same average, opposite stories — SD reveals which dataset to trust.
What else comes with the result?
Population and sample SD together with variance, mean, median, range, and count — one paste serves the whole lab report.
How many values can I enter?
Dozens to hundreds paste cleanly as comma or space separated lists. Strip labels and units first — stray text breaks parsing.
Is my dataset uploaded?
No — statistics compute locally in your browser. Data never leaves your device.
What does the default dataset produce?
10, 12, 23, 23, 16, 23, 21, 16 gives count 8, mean 18.0000, median 21 (upper-middle of the sorted list), range 10–23, population SD 4.8990, sample SD 5.2372, variance 24.0000. You need at least 2 numeric values, comma/space/tab separated — stray text blanks the result.
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Last updated October 2026