Ape Index Calculator: What’s Your Ape Index?

Ever wonder what your ape index is? Find out with our ape index calculator!

Ape Index Calculator

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What Is the Ape Index?

The ape index is a measurement of how your wingspan (aka arm span) compares to your height. It’s believed that most people’s wingspan is equivalent to their height, meaning most people have a neutral ape index or, put another way, an ape index ratio of 1.

The ape index is measured because in sports like rock climbing, swimming, boxing, and basketball it’s considered an advantage to have long arms for your height.

How to Calculate Your Ape Index

There are two ways to calculate your ape index: divide your wingspan by your height or subtract your height from your wingspan.

Method #1: Wingspan to Height Ratio

How to calculate: Wingspan / Height

Example: Daniel Woods, arguably the greatest boulderer of all time, is 5′ 8″ (68 in) with a 72-inch wingspan. To calculate his ape index as a ratio you divide his wingspan by his height:

72 in / 68 in = 1.06

When expressed as a ratio, Woods has an ape index of 1.06.

Bottom line: The typical ape index ratio is 1. A number greater than one means your wingspan is greater than your height, and a number less than one means your height is greater than your wingspan. The advantage of expressing your ape index as a ratio is that it will stay the same regardless of whether you calculate it using inches or centimeters.

Method #2: Difference Between Wingspan & Height

How to calculate: Wingspan – Height

Example: Daniel Woods is 5′ 8″ (68 in or 172.7 cm) with a 72-inch (182.9 cm) wingspan. To calculate the difference you simply subtract his height from his wingspan:

In inches: 72 in – 68 in = 4 in

In centimeters: 182.9 cm – 172.7 cm = 10.2 cm

When expressed as the difference between wingspan and height, Woods has a +4 ape index in inches, or a +10.2 ape index in centimeters.

Bottom line: This is the most common way climbers express their ape index. Using this method, the typical ape index is 0. The downside to this method is that, unless it’s 0, your ape index changes depending on whether you’re using inches or centimeters.

Ape Indices of Famous Climbers

Note: If you know the ape index of a famous climber not listed here, put it in the comments below along with the source and we’ll add it to the list!

Compare your ape index with some of the world’s greatest climbers:

ClimberWingspan (in)Height (in)Ape Index 1 (W / H)Ape Index 2 (W - H)
Average69.367.21.03+2.1
Kai Lightner*82.075.01.09+7.0
Daniel Woods72.068.01.06+4.0
Dave Graham**74.070.01.06+4.0
Ethan Pringle74.070.01.06+4.0
Jan Hojer78.074.01.05+4.0
Paul Robinson74.071.01.04+3.0
Chris Sharma**74.572.01.03+2.5
Sasha DiGiulian64.062.01.03+2.0
Emily Harrington64.062.01.03+2.0
Alex Puccio65.063.01.03+2.0
Angy Eiter62.260.61.03+1.6
Jonathan Siegrist67.065.51.02+1.5
Jimmy Webb73.072.01.01+1.0
Nalle Hukkataival68.568.01.01+0.5
Alex Megos68.068.01.000
Hazel Findlay62.062.01.000
Lynn Hill**62.062.01.000
Babsi Zangerl63.063.80.99-0.8

* In this video, Kai Lightner says his ape index is +18. Because the video is of him training at Café Kraft in Germany, I’ve interpreted it as 18 centimeters, or about 7 inches. A +7-inch ape index is already incredible. +18 inches would be downright ludicrous.

** This photo is where I found the reported ape indices of Chris Sharma, Dave Graham, and Lynn Hill. Sharma’s is located near the top right and appears to read “2½.” Graham’s is located near the top left in blue and appears to read “4.” Hill’s is located at the very bottom and appears to read “0.”

Analysis

The handful of professional climbers in the table above have, on average, a positive ape index. Put simply, they tend to have long arms for their height.

(Take these numbers with a grain of salt. The data is mostly self-reported.)

Keep in mind that our sample is quite small. If these averages held true across a larger sample of pro climbers, they would suggest that a positive ape index is an advantage in climbing at a high level.

However, there are a few notable exceptions:

  • Lynn Hill, the first person to free The Nose on El Cap and one of the most famous climbers of all time, has an ape index of 0 (or, an ape index ratio of 1)
  • Babsi Zangerl, one of the best trad climbers in the world, has a -0.8 ape index (or, an ape index ratio of 0.99)
  • Alex Megos, one of the best sport climbers in the world, has an ape index of 0 (or, an ape index ratio of 1)

Is a Positive Ape Index Good for Climbing?

It’s commonly believed that a positive ape index (or an ape index ratio greater than 1) is good for rock climbing.

Indeed, Matt Samet, editor of Climbing Magazine, writes in his book The Climbing Dictionary: “A positive ape index, in which your wingspan exceeds your height, is a bonus. … A negative ape index is rarely an asset.”

It’s easy to see why climbers by and large believe this. It seems to make intuitive sense: the longer your arms, the greater your reach advantage relative to other climbers your height.

However, while researching for this article I got curious about whether there was any data backing up this belief. So I decided to do a bit of digging.

Let’s look at the science.

Do Elite Climbers Have High Ape Indices?

Some studies have measured the ape indices of elite climbers.

A lot of them are plagued by the issue of small sample sizes, but in most of them, on average the climbers have ape index ratios greater than 1. Recall that an ape index ratio of 1 is considered typical.

It seems that on average elite climbers have higher ape indices than the general population.

Does a High Ape Index Make You a Better Climber?

Though on average elite climbers appear to have high ape indices, when researchers have compared ape index to climbing performance they have often struggled to find a positive correlation.

One study summed it up well:

“[E]lite climbers usually possess an index higher than 1.00 but it was not proven that the ape index correlates with climbing performance.”

Trainable Factors Are More Predictive of Climbing Ability

Whether or not a high ape index is good for climbing, you can’t change yours. You’re stuck with what you’ve got.

(Well, at least that’s how it would seem. I found a couple suggestions on internet forums and one on the ape index Wikipedia entry that certain exercises can improve your ape index over time. I haven’t found any data to back up this claim.)

Fortunately, things that are under your control have been shown to correlate positively with climbing ability.

As one study put it, “the variables found to explain most variance in sport climbing ability are trainable.”

What are these variables?

They’re things like low body fat percentage and grip strength to body mass ratio — variables you can directly affect through training.

Remember that the next time you find yourself using your -2 ape index as an excuse for why you’re not climbing as hard as you’d like. 😉