Syntax
TRIMMEAN(array, percent)
| Parameter | Description |
|---|---|
| array | Parameter of the TRIMMEAN function. |
| percent | Parameter of the TRIMMEAN function. |
Examples
Olympic-style scoring
Formula
=TRIMMEAN(B2:B12, 0.2)
Trims 20% of values (10% from each end) from 11 judge scores. With 11 values, 1 is removed from each end (2 total), and the remaining 9 are averaged.
Salary average without extremes
Formula
=TRIMMEAN(C2:C500, 0.1)
Removes the top and bottom 5% of salaries before averaging. This prevents CEO pay from skewing the average.
Robust sensor reading
Formula
=TRIMMEAN(D2:D1000, 0.05)
Trims 2.5% from each tail of 999 sensor readings, removing noise spikes before calculating the mean.
Common Errors
#NUM!
Returned when percent is less than 0 or greater than or equal to 1. It must be between 0 (no trim) and just under 1.
#VALUE!
Non-numeric arguments.
Tips
Percent is split between both ends
A percent of 0.2 trims 10% from the bottom AND 10% from the top — not 20% from each end. Total removed is 20%.
Number trimmed is rounded down
If 10% of 15 values = 1.5, only 1 value is trimmed from each end (rounds down). The formula always trims whole values.
TRIMMEAN(data, 0) equals AVERAGE
Setting percent to 0 trims nothing, giving you a standard average. Increase the percentage to progressively dampen outlier influence.
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