What this calculator does
Ape index works out how your arm span compares to your height, a rough climbing-reach indicator. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaApe index (ratio) = wingspan / height; ape index (difference) = wingspan − height
The inputs explained
| Field | What to enter |
|---|---|
| Wingspan (fingertip to fingertip, arms out) (cm) | A number, measured in cm. Starts at 178. |
| Height (cm) | A number, measured in cm. Starts at 175. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with wingspan (fingertip to fingertip, arms out)
Every other input is held at the calculator’s starting values while wingspan (fingertip to fingertip, arms out) varies. Select any row to load that scenario into the calculator.
How the answer changes with wingspan (fingertip to fingertip, arms out)
| Wingspan (fingertip to fingertip, arms out) (cm) | Ape index (difference) | Ape index (ratio) | Reading |
|---|---|---|---|
| 89 | -86.0 cm | 0.509 | Negative: wingspan shorter than height |
| 134 | -41.0 cm | 0.766 | Negative: wingspan shorter than height |
| 178 | +3.0 cm | 1.017 | Neutral: wingspan close to height |
| 267 | +92.0 cm | 1.526 | Positive: wingspan longer than height |
| 356 | +181.0 cm | 2.034 | Positive: wingspan longer than height |
| 534 | +359.0 cm | 3.051 | Positive: wingspan longer than height |