Ape Index Calculator
Calculate your ape index to discover the relationship between your wingspan and height. Find out if you have a positive, neutral, or negative ape index and what it means for climbing and other sports.
Your Ape Index
What Is Ape Index?
The ape index measures the relationship between your arm span (wingspan) and your height. This measurement originated in the rock climbing community, where it became a popular metric for assessing body proportions relevant to athletic performance. The term draws from the observation that apes typically have longer arms relative to their body height compared to humans.
According to Leonardo da Vinci’s famous Vitruvian Man drawing, a perfectly proportioned human has an arm span equal to their height. Most people fall close to this 1:1 ratio, though variations exist across individuals. Athletes in certain sports, particularly climbing, swimming, and combat sports, often display arm spans that exceed their height.
Key Point: Your ape index reflects your natural body proportions and can provide insight into which sports or activities might suit your physical attributes. However, it represents just one factor among many that contribute to athletic performance.
How to Calculate Ape Index
There are two accepted methods for calculating your ape index, both producing valid results that express the same relationship differently.
Ratio Method
This method produces a decimal number where 1.0 represents a neutral index. Values above 1.0 indicate a positive ape index (longer arms), whilst values below 1.0 indicate a negative ape index (shorter arms).
Example: If you have a 180cm wingspan and 175cm height, your ape index would be 1.03 (positive).
Difference Method
This method shows the absolute difference between your wingspan and height. A result of 0 is neutral, positive numbers indicate longer arms, and negative numbers indicate shorter arms.
Example: With a 180cm wingspan and 175cm height, your ape index would be +5cm (positive).
How to Measure Your Wingspan
Stand with your back against a wall and extend both arms horizontally, parallel to the floor. Keep your arms straight and measure from the tip of one middle finger to the tip of the other middle finger. Having someone assist you produces the most accurate measurement, though you can mark the wall at each fingertip if measuring alone.
How to Measure Your Height
Stand barefoot with your back flat against a wall, keeping your heels together and your head level. Stand as straight as possible without slouching. Mark the wall at the highest point of your head, then measure from the floor to this mark. Take measurements at the same time of day, as your height can vary slightly throughout the day due to spinal compression.
Understanding Your Results
Positive Ape Index
A positive ape index means your wingspan exceeds your height. When calculated as a ratio, this produces values greater than 1.0. When calculated as a difference, this produces positive numbers. Many elite climbers and swimmers possess positive ape indices, as longer arms can provide advantages in these activities.
Neutral Ape Index
A neutral ape index indicates your wingspan approximately equals your height. This represents the most common body proportion in the human population. The ratio method produces values near 1.0, whilst the difference method produces values near 0. Having a neutral ape index presents no inherent disadvantages in most sports.
Negative Ape Index
A negative ape index means your wingspan is shorter than your height. The ratio method produces values below 1.0, whilst the difference method produces negative numbers. This body type is less common but not necessarily disadvantageous, as technique, strength, and flexibility remain more important factors in most athletic pursuits.
Sports Where Ape Index Matters
Rock Climbing
Longer arms allow climbers to reach distant holds more easily, potentially reducing the need for dynamic movements. However, technique and finger strength often matter more than arm length.
Swimming
A positive ape index can provide mechanical advantages in swimming, allowing for longer strokes and more efficient water displacement with each arm movement.
Boxing & MMA
Greater reach allows fighters to strike opponents whilst remaining outside their opponent’s range, providing both offensive and defensive advantages.
Basketball
Longer arms benefit players in shooting, blocking, and rebounding. Many professional basketball players possess significantly positive ape indices.
Does Ape Index Predict Athletic Success?
Scientific research presents mixed findings on the relationship between ape index and athletic performance. Whilst some studies suggest correlations between positive ape indices and success in specific sports, other research indicates that trainable factors like strength, technique, and experience outweigh the influence of body proportions.
Many world-class athletes across various sports possess neutral or even negative ape indices, demonstrating that this single measurement cannot determine athletic potential. Physical attributes work together with training, mental preparation, and technical skill to create successful athletes.
Frequently Asked Questions
What is a good ape index for climbing?
A positive ape index (ratio above 1.0 or positive difference) is generally considered favourable for climbing, as it provides greater reach. However, many successful climbers have neutral or negative ape indices. Elite climbers typically show values between 1.0 and 1.07 (or +0 to +10cm), though climbing ability depends far more on technique, finger strength, and core stability than arm length alone.
Can exercise change my ape index?
No, exercise cannot change your ape index, as it represents the ratio between fixed skeletal measurements. Your height and wingspan are determined by bone length, which does not change significantly after you finish growing (typically in late adolescence). Whilst training can improve your performance in sports where ape index matters, it cannot alter the underlying measurement itself.
What was Michael Phelps’ ape index?
Olympic swimmer Michael Phelps has an ape index of approximately 1.052 (ratio method) or +10cm (difference method). His wingspan measures about 201cm whilst his height is 191cm. This positive ape index contributed to his swimming efficiency, though his success also relied on exceptional technique, training, and other physical attributes.
Is wingspan always equal to height?
No, wingspan is not always equal to height. Whilst Leonardo da Vinci’s Vitruvian Man depicts this 1:1 ratio as ideal human proportions, real humans show considerable variation. Most people have wingspans within a few centimetres of their height, but individuals can have significantly longer or shorter arm spans relative to their body height.
Should I worry if I have a negative ape index?
No, a negative ape index does not limit your athletic potential or indicate any health concerns. It simply describes your body proportions. Many successful athletes across various sports have negative ape indices. Focus on developing your strengths, improving technique, and building the specific skills required for your chosen activities rather than worrying about fixed body measurements.
Which measurement method should I use?
Both the ratio method and difference method are valid, producing equivalent information in different formats. The ratio method allows easier comparison across people using different measurement systems (metric vs imperial), as it produces a dimensionless number. The difference method provides a more intuitive sense of the actual length difference between your arms and height. Choose whichever method makes more sense to you.