Free Standard Deviation Calculator
Paste any dataset to get population and sample standard deviation, both variances, the mean and count — the complete spread picture in one click.
How to Use the Standard Deviation Calculator
- Paste your dataset into the box.
- Click Calculate SD.
- Get population & sample SD, variance and mean.
Features
Computes squared deviations from the mean, dividing by N for population (σ) and N−1 for sample (s) statistics, with four-decimal precision.
Benefits & Use Cases
Students verify stats homework, researchers summarize measurements, and quality teams quantify process consistency.
Tips
Use sample SD (s) when your data is a sample of something bigger — that’s the right choice for most real-world datasets.
Frequently Asked Questions
What is standard deviation?
The typical distance of data points from the mean — a measure of spread. Small SD = clustered data.
Population vs sample SD?
Population (σ) divides by N for complete data; sample (s) divides by N−1 to correct for sampling.
What is variance?
Standard deviation squared — the same spread information in squared units.
How many data points do I need?
At least two; more points give a more meaningful SD.
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