Ape Index Calculator

What Is the Ape Index Calculator?

The ape index compares your arm span (wingspan) to your height. A value near 1.0 is typical, while a value above 1.0 means your arms are longer than your height. The measure is popular in climbing, swimming, basketball and combat sports, where reach can influence performance. For strength tools that interact with limb length, try the Bench Press Calculator and the One Rep Max Calculator.

How the Calculation Works

The tool offers two definitions. The ratiometric ape index divides wingspan by height:

$$\text{Ratio Ape Index} = \frac{\text{Wingspan}}{\text{Height}}$$

The absolute ape index subtracts height from wingspan and keeps the sign:

$$\text{Absolute Ape Index} = \text{Wingspan} - \text{Height}$$

A ratio above 1.02 is read as a positive ape index, below 0.98 as negative, and in between as neutral. Measurements can be entered in centimetres or inches.

Worked Example

Michael Phelps is listed at 193 cm tall with a 203 cm arm span. His ratio ape index is 203 / 193 = 1.052, and his absolute ape index is 203 - 193 = +10 cm, both clearly positive. By contrast, a player with a 200 cm span and 205 cm height would score 200 / 205 = 0.976, a negative index. The average arm-span-to-height ratio among NBA players is about 1.063.