Exceljet

Quick, clean, and to the point

Excel TRIMMEAN Function

Excel TRIMMEAN function
Summary 

The Excel TRIMMEAN function calculates mean (average) while excluding outliers. The number of data points to exclude is provided as a percentage.

Purpose 
Calculate mean excluding outliers
Return value 
Calculated mean
Syntax 
=TRIMMEAN (array, percent)
Arguments 
  • array - Values to trim and average.
  • percent - The number of data points to exclude from the calculation.
Usage notes 

The Excel TRIMMEAN function calculates mean (average) while excluding outliers. The number of data points to exclude is provided as a percentage.

TRIMMEAN works by first excluding values from the top and bottom of a data set, then calculating mean. The number of data points is provided as a percentage. The percentage can be input either in decimal format or percent format:

=TRIMMEAN(A1:A100,0.1) // exclude 10%
=TRIMMEAN(A1:A100,10%) // exclude 10%
=TRIMMEAN(A1:A100,0.2) // exclude 20%
=TRIMMEAN(A1:A100,20%) // exclude 20%

It's important to note that TRIMMEAN rounds excluded data points down to the nearest multiple of 2. For example, with 50 data points, 10% equals 5 values. In this case, TRIMMEAN will round 5 down to 4, then exclude two values from the top, of the data set, and two values from the bottom of the data set.

Related functions 
Excel AVERAGE function
Excel AVERAGE Function

The Excel AVERAGE function returns the average of values supplied as multiple arguments. AVERAGE can handle up to 255 individual arguments, which can include numbers, cell references, ranges, arrays, and constants.

Excel AVERAGEIF function
Excel AVERAGEIF Function

The Excel AVERAGEIF function computes the average of the numbers in a range that meet the supplied criteria. The criteria for AVERAGEIF supports logical operators (>,,=) and wildcards (*,?) for partial matching....

Excel MODE function
Excel MODE Function

The Excel MODE function returns the most frequently occurring number in a numeric data set. For example, =MODE(1,2,4,4,5,5,5,6) returns 5.

Good links 
Microsoft TRIMMEAN function documentation

Excel Formula Training

Formulas are the key to getting things done in Excel. In this accelerated training, you'll learn how to use formulas to manipulate text, work with dates and times, lookup values with VLOOKUP and INDEX & MATCH, count and sum with criteria, dynamically rank values, and create dynamic ranges. You'll also learn how to troubleshoot, trace errors, and fix problems. Instant access. See details here.

500 Formula Examples, thoughtfully explained.