About the Interquartile Range Calculator
Compute the interquartile range (IQR = Q3 − Q1) and the fences used to flag outliers.
Also known as: iqr calculator, interquartile range, outlier calculator, inner fences.
How to use this calculator
- Enter data set.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
IQR = Q3 − Q1 · fences = Q1 − 1.5·IQR, Q3 + 1.5·IQR
Worked example
Using the values pre-filled in the calculator above:
- Data set: 1, 3, 4, 5, 5, 6, 7, 11, 25
the calculator returns:
- IQR: 3
- Q1: 4
- Q3: 7
- Lower fence: -0.5