glunty Statistics Calculator (Mean, Median, SD)
Paste numbers, get mean, median, mode, range, and standard deviation. All local.
- Runs in your browser
- No sign-up
- No watermark
- No installs
Summary
Variance and standard deviation
What this tool does
Computes descriptive statistics for a list of numbers as you type. Enter values separated by commas, spaces, or new lines, and the tool reports the count, sum, mean (average), median, mode, minimum, maximum, and range, plus both the population and sample variance and standard deviation. Every calculation happens locally in your browser; nothing is uploaded.
How to use it
Paste or type your numbers into the box. Separators are flexible: commas, spaces,
tabs, and new lines all work, and you can mix them freely. Results update instantly.
Non-numeric tokens are ignored (and counted), so a stray word or unit will not break
the math. Use Copy results to grab the full summary, or
Clear to start over. Example: the numbers
2, 4, 4, 4, 5, 5, 7, 9 give a mean of 5, a median of 4.5, a mode of 4,
a population standard deviation of 2, and a sample standard deviation of about 2.138.
Common use cases
- Summarizing test scores, survey responses, or grades at a glance.
- Checking the spread of measurements or timings from a quick experiment.
- Finding the median when a few outliers make the mean misleading.
- Getting the population or sample standard deviation for a stats homework problem.
- Sanity-checking a spreadsheet formula (AVERAGE, MEDIAN, STDEV) against an independent calculation.
Common pitfalls
- Population vs sample. Dividing by N (population) and by N-1 (sample) give different answers, and the gap is largest on small data sets. Pick sample when your numbers are a sample of something bigger; pick population when they are the whole group.
- The mean is not robust. A single extreme value can drag the mean far from the center of the data. When the data is skewed, report the median alongside the mean.
- Mode is not always meaningful. For continuous measurements every value may be unique, giving no mode at all. Mode is most useful for repeated or categorical-style numbers.
- Mind the units. Variance is in squared units; standard deviation is in the original units. Compare spreads using the standard deviation, not the variance.
Frequently asked questions
- What is the difference between mean, median, and mode?
- The mean is the arithmetic average: add every value and divide by the count. The median is the middle value once the numbers are sorted, or the average of the two middle values when the count is even. The mode is the value that appears most often. On skewed data the median is often a better measure of center than the mean, because a few extreme values can pull the mean far from the bulk of the data.
- Population vs sample standard deviation: which one should I use?
- Use the population standard deviation when your numbers are the entire group you care about, where you divide the sum of squared deviations by N. Use the sample standard deviation when your numbers are a sample drawn from a larger population and you want to estimate that population, where you divide by N minus 1 (the Bessel correction). Spreadsheet note: STDEV.P and VAR.P are population; STDEV.S and VAR.S are sample. For real-world measurements, sample is the common default.
- What is the difference between variance and standard deviation?
- Variance is the average of the squared deviations from the mean, so its units are the square of the original units. Standard deviation is the square root of the variance, which puts the spread back into the same units as the data and makes it easier to read. Both describe how spread out the numbers are; a larger value means more spread.
- What happens when there is no mode or more than one mode?
- If every value appears the same number of times, for example when all values appear once, the tool reports no mode, because no single value is more common. If two or more values tie for the highest count the data is multi-modal, and the tool lists all of them. Mean and median are always single numbers, but the mode can be none, one, or many.
- What separators and number formats can I use?
- Separate numbers with commas, spaces, tabs, or new lines, or any mix of those. Negative numbers, decimals, and scientific notation like 1e3 all work. Non-numeric tokens are ignored, and the tool tells you how many it skipped, so a stray label or unit will not break the calculation.
- How does the tool handle empty or invalid input?
- Empty input shows a short prompt instead of results. Tokens that are not valid numbers are skipped and counted, rather than turned into zero, so they do not distort the mean or the standard deviation. You always see how many values were actually used in the calculation.
- Is my data sent to a server?
- No. Every calculation runs in your browser with plain JavaScript. Nothing is uploaded, logged, or stored, so you can safely paste sensitive figures. You can confirm this by opening DevTools and watching the Network tab: there are zero requests while the tool runs.
Cite this tool
For academic, journalistic, or technical references. Pick a format:
Citations use 2026 as the publication year. Access date is left as a fillable placeholder where the citation style expects one.