Ape Index is the difference between your arm span (fingertip to fingertip) and your height. A positive index means your arm span exceeds your height; a negative index means your arms are shorter than your height. The Vitruvian average — popularized by Leonardo da Vinci — is a 1:1 ratio.

Why does Ape Index matter for athletes?

In climbing, a positive Ape Index gives a meaningful reach advantage on big moves. In swimming, longer arms translate to more water displaced per stroke. In boxing, reach can keep an opponent at distance. In basketball, wingspan is often a better predictor of NBA draft potential than height.

How do I measure my arm span?

Stand with your back against a wall and arms outstretched horizontally at shoulder height, palms facing forward. Measure the distance from the tip of one middle finger to the tip of the other. Have someone help — self-measuring is awkward and reduces accuracy. Measure in centimeters for the most precise ratio.

What is a "good" Ape Index?

For most sports, a positive index of 2-5 cm is a meaningful advantage. Elite climbers often have +5 to +10 cm. NBA players average a wingspan-to-height ratio of about 1.06 (so a 6'6" player typically has a ~6'10" wingspan). For the general population, the average is roughly 1:1, so anything positive is above average.

Can I change my Ape Index?

No — both arm span and height are determined by your skeletal structure once growth plates close (typically late teens/early twenties). What you can do is develop the strength, mobility, and technique to take full advantage of whatever reach you have.

Ape Index Calculator

Compare your arm span to your height. A positive ape index is a known advantage in climbing, swimming, and basketball.

Calculator

About Ape Index

Ape Index — sometimes called the gorilla index or wingspan ratio — compares arm span to height. The Vitruvian Man drawing assumed a 1:1 ratio: a person's arm span equals their height. In reality, most people deviate slightly. Climbing, swimming, basketball, and combat sports all reward a positive index where arms extend beyond the height baseline.

How to Interpret Your Result

A positive index (arm span > height) is common in athletes whose sport rewards reach. A neutral index (arm span ≈ height) matches the Vitruvian average. A negative index is less common but does not affect health — it just means your sport-specific reach advantage is reduced. The ratio (arm span ÷ height) is sometimes more useful than the absolute difference, especially for comparing across body sizes.

Formula

Ape Index = Arm Span (cm) − Height (cm)

Ape Ratio = Arm Span ÷ Height

Ape Index Reference

IndexInterpretation

< −5 cmNotably short reach

−5 to +1 cmAverage / Vitruvian

+2 to +5 cmAbove average reach

+5 to +10 cmStrong reach advantage (climber/swimmer territory)

> +10 cmExceptional reach

Medical Disclaimer

Ape Index is a structural measurement, not a health indicator. It is most useful in sport-specific contexts.

Ape Index Calculator

About Ape Index

How to Interpret Your Result

Formula

Ape Index Reference

Medical Disclaimer

Frequently Asked Questions

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Track Your Ape Index Over Time