How this calculator works
Wingspan is measured fingertip to fingertip with the arms stretched horizontally. The ape index divides wingspan by height, so 1.03 means the arms span three percent more than the body is tall. Some people prefer the difference in centimetres, which is easier to picture: a 180 cm wingspan on a 175 cm frame is an index of 1.029 and a difference of 5 cm. The same measurements can be rearranged to find wingspan or height from a target index.
Formula
Ape index = wingspan / height. Difference = wingspan - height. Wingspan = index x height. Height = wingspan / index.
Worked example
A climber 175 cm tall with a 180 cm wingspan has an index of 180 / 175 = 1.029 and a difference of 5 cm. To reach an index of 1.05 at the same height, the wingspan would need to be 1.05 x 175 = 183.8 cm.
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Frequently asked questions
What is an average ape index?
Adult ratios cluster close to 1.00, with most people within about five percent either way. Values above 1.05 or below 0.95 are less common but still occur naturally.
Does a high ape index make a better climber?
Reach can help on some moves, but technique, strength, finger endurance and body composition matter more. The index is a descriptive measurement, not a performance score.
How should I measure wingspan?
Stand with your back to a wall, arms out horizontally at shoulder height, and measure from the tip of one middle finger to the other. Use the same posture each time, because shrugging or poor posture changes the result.