IQR Calculator
Calculate the interquartile range (Q3 − Q1) as a robust measure of spread.
Inputs
IQR
6.0000
Q1
5.0000
Q3
11.0000
Step by step
Values used
Data (comma separated) = 2, 4, 6, 8, 10, 12, 14
Formula applied
IQR = Q3 − Q1
IQR
= 6.0000
Q1
= 5.0000
Q3
= 11.0000
How it works
The interquartile range (IQR) is Q3 minus Q1. It measures the spread of the middle 50% of data and is resistant to outliers, unlike the full range.
Formula
IQR = Q3 − Q1
- Q1
- First quartile
- Q3
- Third quartile
Frequently Asked Questions
Why is IQR preferred over range?
IQR ignores the extreme values and only measures the spread of the middle half of the data, making it robust against outliers.
How is IQR used to detect outliers?
Values below Q1 − 1.5×IQR or above Q3 + 1.5×IQR are flagged as outliers using Tukey's fence method.