Enter the average value of Q1 and Q3, and the interquartile range into the calculator to determine the low and high outliers.

Outlier Formula

The following equation can be used to calculate the values of the outliers.

L = Q1 – (1.5* IQR)

H = Q3 + (1.5*IQR)

  • Where L is the lower outlier
  • H is the higher outlier
  • Q1 and Q3 are the average values of those quartiles
  • IQR is the interquartile range

Outlier Definition

An outlier is defined as the extreme values of a set of data that vary the most from the mean or norm.


What is an outlier?

An outlier is a term used in statistics to describe extreme values that vary from the norm of a data set. In other words, the highest and lowest values of a data set that sit apart from the rest.

What causes outliers?

Outliers occur either by chance or by measurement error.

How many outliers are there?

There can be any number of outliers, but often times the outliers can be the sample maximum and minimums as the formula above calculates.

outlier calculator
outlier formula