Standard Deviation Calculator
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Paste a list of numbers — separated by commas, spaces, or new lines — and this calculator returns the mean, variance, and standard deviation for both a whole population and a sample, along with the sum, count, min, max, and range. Everything is computed in your browser.
How to use
- Paste your numbers, separated by commas, spaces, or lines.
- Read the mean and standard deviation below.
- Use the population value for a full dataset, or the sample value for a sample.
How it works
First the mean (average) is found by dividing the sum by the count. Then each number's difference from the mean is squared and these are added up. Dividing that total by n gives the population variance; dividing by n−1 gives the sample variance, which corrects for estimating from a sample. The standard deviation is the square root of the variance.
Features
Population & sample
Get both σ (population) and s (sample) at once.
Full summary
Also shows sum, count, mean, min, max, and range.
Flexible input
Accepts commas, spaces, new lines, decimals and negatives.
Private & instant
All math runs in your browser; nothing is uploaded.
When to use it
Statistics homework
Check the spread of a dataset and your working.
Lab & science
Summarize the variability of measurements.
Grades & scores
See how consistent a set of results is.
Quick analysis
Get the spread of any pasted numbers fast.
Notes
- Use population (σ) for a complete dataset.
- Use sample (s) when the numbers are a sample of a larger group.
- Sample values need at least two numbers.
- All calculations run on your device; nothing is uploaded.
FAQ
- What's the difference between population and sample?
- Population divides by n; sample divides by n−1 to correct for estimating from a sample. Use sample when your data is a subset of a larger group.
- What input does it accept?
- Numbers separated by commas, spaces, or new lines, including decimals and negatives.
- Why is the sample value blank?
- Sample variance and standard deviation need at least two numbers, since they divide by n−1.
- What is variance?
- The average of the squared differences from the mean. Standard deviation is its square root, in the original units.
- Is my data uploaded?
- No. Everything is calculated in your browser and nothing leaves your device.