Range Calculator
The range is the simplest measure of spread: the gap between the largest and smallest values.
Range of a list
Formula
range = maximum − minimum
Worked example
Range of 14, 22, 9, 31, 17, 25
- Largest value: 31
- Smallest value: 9
- 31 − 9 = 22
The range is 22.
Range vs interquartile range
Because the range depends only on the two most extreme values, a single unusual reading can make it very large. The interquartile range (IQR = Q3 − Q1) measures the spread of the middle half of the data and ignores the extremes, so it is a steadier guide. A common rule flags values more than 1.5 × IQR below Q1 or above Q3 as possible outliers.
Everyday uses
- The spread of temperatures over a week.
- The difference between the highest and lowest quotes you received.
- Checking the consistency of repeated measurements.