Ape Index Calculator
Positive, neutral or negative? Measure your wingspan against your height.
Result
How it is calculated
The tool takes two measurements in centimetres and reports ape index = arm span − height, in cm and in inches (cm ÷ 2.54), with a plus or minus sign. It also gives the ratio arm span ÷ height to three decimals, where 1.000 means span equals height. The category uses a 2.5 cm band: a difference of +2.5 cm or more is a positive ape index, −2.5 cm or less is negative, and anything in between is shown as neutral (even). Both values must be above zero; the tool does not check that they are plausible for a human body. Arm span is measured fingertip to fingertip with the arms stretched out at shoulder height.
Worked example
Your arm span is 182 cm and your height is 175 cm. Difference = 182 − 175 = +7.0 cm, which is +2.8 in. Ratio = 182 ÷ 175 = 1.040. Because +7.0 is above the 2.5 cm threshold, the category is a positive ape index. With a 177 cm span and the same height, the difference would be only +2.0 cm and the tool would call it neutral, even though the ratio is still above 1.
Common mistakes
- Using a reach measured from the wall to the fingertips with one arm and doubling it, rather than the full fingertip-to-fingertip span.
- Measuring height with shoes on or with a slouch, or arm span with the arms hanging below shoulder level; both shift the difference by centimetres.
- Mixing units: height in feet and inches typed into the centimetre field, or span in centimetres and height in inches.
- Reading the ratio and the difference as the same thing: 1.040 is a ratio, +7.0 cm is a difference, and the category is decided by the difference.
- Treating a positive ape index as a guarantee of climbing or basketball ability; it is one body proportion, and a difference of 2 cm is classed neutral.
About this calculator
Ape index compares arm span to height, expressed either as the difference in centimeters (arm span minus height) or as a ratio (arm span divided by height). A positive ape index means your wingspan exceeds your height — an ape-like build — while a negative index means your height exceeds your reach, and zero means they’re equal; most people fall within a couple of centimeters of zero either way.
Rock climbers popularized the term because a longer reach relative to height is a genuine mechanical advantage for spanning holds on a route, and it’s commonly discussed in climbing communities alongside grip strength and finger strength as a factor (though far from the only one) in climbing performance. It also gets referenced in basketball scouting, where wingspan is measured separately from height to estimate a player’s effective reach on defense and rebounding, and in boxing, where a longer reach affects range in a fight.
This calculator takes your arm span and height and returns your ape index in centimeters and as a ratio.
Was this helpful?
You can pick up to 3 reactions.
Popular calculators
Loan Calculator
Monthly payment, total interest and full amortization schedule.
Percentage Calculator
Percent change, percent of, and ratio calculations.
Discount Calculator
Calculate final price, savings, and discount amount.
BMI Calculator
Body mass index from height and weight (metric or imperial).
Age Calculator
Compute your exact age in years, months and days from a birth date.
Compound Interest Calculator
Calculate the final amount and interest earned with compounding.
All Calculators
No calculators found
Comments (0)