Ape Index Calculator
Ape index — arm span compared with height — the climber’s and swimmer’s measure of reach.
Measure your arm span fingertip to fingertip with arms out straight, and your height.
How the ape index calculator works
Measure your arm span fingertip to fingertip with arms out straight, and your height. The ape index is span minus height (positive means longer arms than you are tall) or span divided by height. Most people sit near zero; an index of +5 cm or more is a real reach advantage on the wall.
Formula: ape index = arm span − height (or span ÷ height)
Worked examples
| Inputs | Ape index | Note |
|---|---|---|
| 183 cm span, 178 cm tall | 5 | +5.0 cm |
| 72 in span, 70 in tall | 2 | +2.0 in |
| Neutral | 0 | 0.0 |
FAQFrequently asked questions
What is a positive ape index?
An arm span longer than your height. It is common in tall people and among elite climbers — many have +5 cm or more — but plenty of top climbers are neutral or negative, so it is an advantage, not a requirement.
How do I measure arm span?
Stand against a wall with arms out horizontally, palms forward, and measure fingertip to fingertip — ideally with someone else holding the tape. Measure height without shoes.
Should I use the difference or the ratio?
Climbers quote the difference in centimeters or inches; the ratio (span ÷ height, about 1.00 for most people) does not depend on units. The calculator shows both.
Is a longer reach always better for climbing?
It helps on reachy moves, but long arms are also more leverage to hold and a heavier upper body to lift. Technique and finger strength matter more.
Where these figures come from
- World Handicap System — Rules of Handicapping — the score differential and handicap index formula
- International Cricket Council — Playing Conditions — over structure and run-rate definitions
- Major League Baseball — Official Rules — the published definitions for baseball statistics
Last checked: September 2026. Formulas follow the governing bodies where one publishes them — the World Handicap System for golf, the ICC playing conditions for cricket run rates.