Interquartile Range Calculator
Calculate the interquartile range, Q3 − Q1, from a data set.
What is IQR?
The interquartile range is the width of the middle half of the data: Q3 minus Q1. It is immune to the largest and smallest quarters entirely, which is why it is the spread measure used to define what counts as an outlier rather than the full range.
How it works
The quartiles come from the same pass that produces every other statistic on the page, so the IQR, the fences at Q1 − 1.5 × IQR and Q3 + 1.5 × IQR, and the outlier page can never disagree about where a value falls. The fences are printed even though this page does not flag anything, because they are what makes the number useful beyond a box-plot width.
- Enter your input. Type or paste your input into the field above — the tool responds instantly.
- Review the result. Output updates live as you type. Everything runs entirely in your browser.
- Copy or download. Use the Copy button to grab the result, or Download to save it as a file.
Examples
Realistic sample
Type or paste any realistic input — the tool computes the result locally and instantly.
Common mistakes
Expecting a server round-trip
Nothing is uploaded — every tool in this category runs entirely in your browser.