How to Calculate a Trimmed Mean with TRIMMEAN

TRIMMEAN drops the highest and lowest values before averaging — the way diving and skating judges are scored.

You will learn to

• Average after trimming the extremes
• Measure how much one outlier distorted an average
• Decide a winner on trimmed scores

How it works

TRIMMEAN(array, percent) removes a fraction of the data points from the top and bottom, then averages the rest. =TRIMMEAN(B2:B9,0.25) on eight judges’ scores drops the single highest and lowest score. Excel rounds the number removed down to the nearest even number so it can trim equally from both ends.

A trimmed mean sits between the mean and the median: it uses most of the data but isn’t pulled around by a few extreme or biased values. It’s used in judged sports, salary surveys and economic indicators such as trimmed-mean inflation.

=TRIMMEAN(B2:B9,0.25)