Ape Index Calculator

In rock climbing and bouldering, you will often hear climbers complain that a route is "reachy" or that a particular dynamic move requires a massive wingspan. This leads directly to the concept of the Ape Index.

Simply put, the Ape Index is a measurement of your arm span relative to your total height. In a perfectly proportioned human (as illustrated in Leonardo da Vinci's Vitruvian Man), a person's arm span is exactly equal to their height, giving them an Ape Index of zero (or a ratio of 1.0). However, climbers often possess—or at least covet—a positive index, where their arms are longer than their bodies.

How is it Calculated?

There are two primary ways the climbing community expresses this measurement:

• The Subtraction Index (Most Common): Your height is subtracted from your arm span. If you are 175 cm tall but have an arm span of 180 cm, your Ape Index is +5 cm. (In the US, this is typically measured in inches, such as +2").
• The Ratio: Your arm span divided by your height. Using the same numbers above, 180 divided by 175 results in a ratio of 1.028.

How to measure yourself accurately:

Stand barefoot with your back against a flat wall. Extend your arms perfectly horizontal (parallel to the floor) to form a "T" shape. Have a friend measure the exact distance from the tip of your longest finger on your left hand to the tip of your longest finger on your right hand. Do not stretch your shoulders out of their sockets—stand naturally.

Does a Positive Ape Index Actually Help?

Yes and no. A highly positive Ape Index offers distinct mechanical advantages, but it also comes with notable drawbacks.

The Advantages:

• Static Reach: The obvious benefit. You can reach further between holds without having to release your feet from lower footholds.
• Leverage on Slopers: Longer arms can allow you to position your center of gravity lower beneath a volume or sloper, significantly improving the directional friction of your grip.
• Deadpointing: You have a larger "capture box" when throwing dynamically for a hold.

The Disadvantages:

• The Lock-Off Penalty: Longer arms act as longer levers. When you have to perform a deep lock-off (pulling your chin to your hand and holding it), your biceps and back muscles have to work significantly harder than someone with shorter arms.
• The "Box" is Cramped: High-stepping and climbing in a highly compressed "bunched up" position—often required on steep cave routes—can feel incredibly awkward and require extreme hip mobility for climbers with long limbs.

The Ape Index of Elite Climbers

If you have a negative Ape Index, do not despair. While many elite climbers have long wingspans, some of the absolute strongest climbers in history span the entire spectrum of body proportions.

• Lynn Hill (-3 cm): A legendary pioneer of free climbing who made history as the first person to free climb The Nose on El Capitan, proving a negative Ape Index is no obstacle to technical mastery.
• Brooke Raboutou (-3 cm): An Olympic medalist and one of the strongest boulderers in the world, showcasing incredible power despite a negative wingspan ratio.
• Janja Garnbret (0 cm): The undisputed queen of competition climbing and multi-time World Champion who has an Ape Index of exactly zero, dominating through peerless coordination and core tension.
• Adam Ondra (+1 cm): Widely considered the best sport climber of his generation (climbing 9c/5.15d), Ondra relies on hyper-mobility and flawless biomechanics rather than raw reach.
• Magnus Midtbø (+3 cm): A world-class powerhouse and renowned climbing educator whose balanced proportions never held him back from crushing elite grades.
• Chris Sharma (+6 cm): Known for his massive, dynamic throws on deep water solos and iconic Spanish sport routes, Sharma takes full advantage of his positive reach.
• Daniel Woods (+10 cm): One of America's most accomplished boulderers, utilizing his exceptionally long wingspan to excel on massive, powerful outdoor compression lines.