The Ape Index
"Ape index, or ape factor, is a measure of the ratio of an individual's arm span relative to their height. A typical ratio is 1, as identified by the Roman writer, architect and engineer Vitruvius prior to 15 BC."
Ape Index, Wikipedia
There are two versions of the Ape Index:
- Usually it is defined as the ratio of arm span to height:
Ape Index 1 = Arm Span / Height
If you're 175cm tall and your arm span is 180cm your ape index would be 1.028 - For the alternative approach the height is subtracted from your arm span:
Ape Index 2 = Arm Span - Height
Still being 180cm tall and with an arm span of 175cm this alternative ape index would be 5 (cm).
In sports like rock climbing, swimming or boxing some people believe that a positive Ape Index, (a value greater than 1), where the arm span is greater than the height, is a competitive advantage. Others doubt it.
Your Ape Index
So what?
Now you know your monkeyness level, but is it good or bad? It depends, every Ape Index has its own advantages:
- If your Ape Index is not even 1 (Index 1), or negative (Index 2) your friends can call you T-Rex.
- If it is near 1 (Index 1) or 0 (Index 2) some Italians may ask you if they can paint you - naked.

- If it is more than 1 (Index 1) or positive (Index 2) you can pick up things from the ground without bending your knees to much.
So whatever it is, be proud of your Ape Index!
Compare your Ape Index
If you're more the competition type of monkey (or T-Rex, or naked model) these numbers may interest you:
- Boxer Sonny Liston had an incredible Ape Index of 1.158 (Index 1) / 29cm (Index 2).
- German discus thrower Lars Riedel has an Ape Index of 1.055 (Index 1) / 11 cm (Index 2).
- World class swimmer Michael Phelps has an Ape Index of 1.04 (Index 1) / 3 inches (Index 2).
- The guys at Mountain Project asked their forum members about their height and armspan. About 50 people answered (all of them climbers). The average Ape Index was 1.0311 (Index 1) / 2.2 inches (Index 2).
The End
That's all. Now move on, get some bananas or improve your drunken monkey style!