What is the syntax for TRIMMEAN in Excel?

The syntax for TRIMMEAN is: =TRIMMEAN(array, percent)

What is TRIMMEAN used for?

TRIMMEAN calculates the mean after removing a percentage of extreme values from both ends. It's a robust measure of central tendency that reduces the impact of outliers without completely ignoring them like MEDIAN does.

How does the percent parameter work?

The percent specifies the total fraction to exclude, split equally between high and low ends. TRIMMEAN(data, 0.2) removes 10% from each end (20% total). With 100 values, it excludes the 10 lowest and 10 highest, averaging the middle 80.

When should I use TRIMMEAN vs AVERAGE or MEDIAN?

Use AVERAGE for clean data without outliers. Use MEDIAN when outliers are extreme or data is highly skewed. Use TRIMMEAN as a compromise - it's more robust than AVERAGE but uses more data than MEDIAN. Common in grading (drop lowest/highest scores).

Statistical

TRIMMEAN Function in Excel

Returns the mean of the interior of a data set, excluding a percentage of outliers.

Syntax

=TRIMMEAN(array, percent)

Arguments

array (required): Data to average
percent (required): Fraction to exclude (0 to 1)

Examples

=TRIMMEAN(A1:A100, 0.1) - Mean excluding 10% outliers - Result: Trimmed mean

TRIMMEAN for data analysis

Confirm whether you need entire columns, filtered subsets, or distinct values.
Use [COUNTIFS](/functions/countifs/) and [SUMIFS](/functions/sumifs/) for multi-criteria metrics.
Pivot tables complement single-cell statistical formulas for exploration.

Common errors

#NUM! if percent < 0 or >= 1

Use cases

Robust averaging
Outlier handling
Data cleaning

Frequently asked questions

What is TRIMMEAN used for? TRIMMEAN calculates the mean after removing a percentage of extreme values from both ends. It's a robust measure of central tendency that reduces the impact of outliers without completely ignoring them like MEDIAN does.
How does the percent parameter work? The percent specifies the total fraction to exclude, split equally between high and low ends. TRIMMEAN(data, 0.2) removes 10% from each end (20% total). With 100 values, it excludes the 10 lowest and 10 highest, averaging the middle 80.
When should I use TRIMMEAN vs AVERAGE or MEDIAN? Use AVERAGE for clean data without outliers. Use MEDIAN when outliers are extreme or data is highly skewed. Use TRIMMEAN as a compromise - it's more robust than AVERAGE but uses more data than MEDIAN. Common in grading (drop lowest/highest scores).

Editorial review

Reviewed by Excel.Directory Editorial Team. Updated May 2026.