Trimmed Mean Calculator
Drop the extremes and average what's left.
Enter your values
ⓘ Live results
Results
- Trimmed mean
- 9.5
- Plain mean
- 13.375
- Median
- 9.5
- Values removed from each end
- 1
- Values kept
- 7, 8, 9, 10, 11, 12
- Difference from the plain mean
- -3.875
Quick answer
A trimmed mean discards a set percentage of the smallest and largest values before averaging, giving a figure that resists outliers.
trim k% from each tail, then take the mean
How to use the Trimmed Mean Calculator
- 1Paste your data.
- 2Choose how much to trim from each tail — 10% is a common default.
- 3Compare the trimmed mean with the plain mean to see how much the extremes were pulling the average.
Worked example
Using the values the calculator loads with:
Inputs
- Data values5, 7, 8, 9, 10, 11, 12, 45
- Trim from each end12.5 %
Results
- Trimmed mean9.5
- Plain mean13.375
- Median9.5
- Values removed from each end1
- Values kept7, 8, 9, 10, 11, 12
- Difference from the plain mean-3.875
Frequently asked questions
Where is this used in real life?
Olympic gymnastics and diving scores, inflation measures such as trimmed-mean CPI, and any benchmark with noisy outliers.
What trim percentage should I pick?
10% to 20% from each end is typical. Trim 50% and you have simply computed the median.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.