Ape Index Calculator - Wingspan to Height Ratio
Enter your arm span (wingspan) and height to find your ape index two ways: as a ratio (wingspan divided by height) and as a raw difference (wingspan minus height). An index above 1.0, or a positive difference, means your arms are longer than your height - a trait associated with reach advantages in climbing, swimming, boxing, and basketball. Results update as you type, in both metric and imperial units.
What is the ape index?
The ape index, also called the wingspan-to-height ratio or arm span ratio, compares the distance between your outstretched fingertips to your standing height. It was first coined by Frisbee athletes at UC Berkeley in 1975, drawing a playful comparison to the long-armed body plan of great apes. The underlying observation is ancient: the Roman architect Vitruvius noted that a person's arm span tends to equal their height, a relationship later illustrated by Leonardo da Vinci's Vitruvian Man around 1492. When wingspan equals height the ratio is exactly 1.0, often called a "neutral" index. When the arms are proportionally longer the ratio rises above 1.0 (a "positive" index), and when the arms are shorter it falls below 1.0 (a "negative" index). Both the ratio and the raw difference (wingspan minus height) are used in practice depending on the sport or context.
How to measure your wingspan accurately
Stand with your back flat against a wall. Raise both arms to shoulder height, fully extended horizontally at 90 degrees to your body. Spread your fingers and keep your palms facing forward. Have a partner mark the tip of each middle finger on the wall, then measure between the two marks. Alternatively, use a long tape measure from fingertip to fingertip in one pass. Measure your height at the same time of day - ideally morning, since height can decrease by up to 1 cm over the course of a day due to spinal compression. Measuring both at the same session removes that source of error. For best results, repeat each measurement twice and average the readings.
Ape index and sport performance
In rock climbing a longer reach can help span crux sequences between holds and make dynamic moves more accessible, though research is mixed: some studies find wingspan statistically significant for predicting grade, while others show grip strength and body weight-to-strength ratio are stronger predictors. In swimming, longer arms increase stroke length per pull cycle, reducing the number of strokes per lap - Michael Phelps, with a ratio of approximately 1.052, is the most cited example. In boxing and MMA, a longer reach lets fighters land punches while staying outside the opponent's range, though research has found that ape index alone cannot predict who wins MMA bouts. In basketball, NBA players average a ratio of about 1.063, and wingspan helps with shot-blocking, rebounding, and passing lanes. In weightlifting, shorter arms (lower ratio) shorten the range of motion in bench press, while longer arms can advantage the deadlift and Olympic lifts. In all cases, technique, conditioning, and sport-specific skills consistently outweigh reach advantages in determining performance outcomes.
Interpreting your result
A ratio near 1.0 (within about +/-0.02) is close to the population average and is considered neutral. A ratio at or above roughly 1.04 to 1.06 is where most sport-specific advantages begin to be discussed meaningfully. Elite athletes span a wide range: top climbers like Lynn Hill and Brooke Raboutou succeed despite negative indices, while Sergei Pavlovich (UFC) carries a ratio of 1.115. The difference method (wingspan minus height) is often more intuitive for day-to-day use: a value of +5 cm means your arms are 5 cm longer than your height. Neither method is intrinsically better, they carry the same information just expressed differently. What matters more than the number is how you train the body you have.
Ape index in elite athletes
| Athlete / Group | Sport | Approx. ratio | Wingspan vs. height |
|---|---|---|---|
| Michael Phelps | Swimming | 1.052 | +10 cm (3.9 in) |
| Muhammad Ali | Boxing | ~1.04 | Reach notably above height |
| Floyd Mayweather | Boxing | ~1.04 | Reach above height |
| Michael Jordan | Basketball | ~1.05 | +7 cm (2.8 in) |
| Shaquille O'Neal | Basketball | ~1.04 | Above average for height |
| Sergei Pavlovich (UFC) | MMA | 1.115 | +22 cm (8.7 in) |
| Average NBA player | Basketball | ~1.063 | Arms ~6.3% longer than height |
| Average adult (general) | General | ~1.00 | Arms close to equal to height |
| Brooke Raboutou | Rock climbing | <1.0 | Negative index, elite climber |
| Lynn Hill | Rock climbing | <1.0 | Negative index, 1993 Nose free solo |
Approximate ape index ratios for famous athletes and population benchmarks. Individual measurements vary by source.
Frequently asked questions
What is a good ape index for rock climbing?
There is no single "good" threshold. A positive ape index (ratio above 1.0) is generally considered helpful for reaching distant holds and spanning crux sequences. Elite climbers such as Daniel Woods have ratios around 1.06, and many professional climbers fall in the 1.02 to 1.06 range. However, top climbers like Lynn Hill and Brooke Raboutou have negative indices, demonstrating that technique, strength-to-weight ratio, and training volume matter far more. Do not let a neutral or negative result discourage you.
What is the average ape index?
In the general adult population, the average ape index ratio is approximately 1.0 - wingspan roughly equals height, as described by Vitruvius and illustrated in da Vinci's Vitruvian Man. NBA basketball players average approximately 1.063, meaning their arms are about 6.3% longer than their height. The average adult difference (wingspan minus height) is close to zero centimetres.
Is it better to have a positive or negative ape index?
For reach-dependent sports like boxing, basketball, and swimming, a positive ape index (ratio above 1.0, arms longer than height) is generally advantageous. For bench press in weightlifting, a shorter reach can reduce range of motion, which some consider a mechanical advantage. In general fitness, neither is meaningfully "better" - proportions vary naturally across the population and do not predict health outcomes.
What is the difference between the ratio and difference methods?
The ratio divides wingspan by height (e.g. 179 cm / 175 cm = 1.023). The difference subtracts height from wingspan (e.g. 179 cm - 175 cm = +4 cm). Both express the same relationship. The ratio is unit-independent and easier to compare across heights; the difference gives an intuitive sense of how many centimetres or inches your arms extend beyond your height. Either is valid - use whichever is clearest in context.
Can I improve my ape index?
No - the ape index is determined by skeletal proportions set during development. You cannot lengthen your arm bones through exercise or training. What you can improve is the reach advantage you extract from your existing proportions: shoulder mobility, lat flexibility, and technique in sport-specific movement all affect how effectively you use your wingspan.
Does ape index affect basketball performance?
Wingspan is scouted heavily in basketball because longer arms assist with shot-blocking, rebounding, passing, and on-ball defense independent of height. NBA players average a ratio of about 1.063. That said, players like Desmond Bane (nicknamed "T-Rex" for his shorter arms) succeed at the highest level, showing that skill and athleticism dominate over pure proportions.