Is your arm span equal to your height?

Did you know arm span ( or reach ) is approximately equal to height?

We tested this out against a wall using chalk to mark reach and then standing next to the wall to see if it matched height. You should measure from finger tip to finger tip and not have a flat hand as in this photo.


arm span


We found my 6 year old’s arm span did equal his height and my 4 year old was a little taller than hers.

Ape index is the ratio of arm span relative to their height. So my little boy had an ape index of 1.

A arm span greater than height is thought to be advantageous in some sports such as swimming, as longer arms may give greater propulsion. A shorter arm span is useful for weight lifters as they don’t have to lift the weight as high.

Can you work out your Ape Index?

Can you work out how many feet tall you are too?

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Author: Emma Vanstone

Science Sparks, is a site dedicated to making Science fun for kids. I’d love you to follow me on my Google Profile+.

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  1. My little ones love this too! Great fun. I didn’t know it had a proper name though! (And apparently your foot is the length of your forearm too.)
    Emma recently posted…Paper Plate Frog MaskMy Profile

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    • I keep meaning to try that one!

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    • Ha ha, good point!

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  2. This is so simple but a really fun idea. Thanks for the inspiration.

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  3. I herd this along time ago on Braniac I think so have added their URL! but when I checked it my Span of my Arm’s is 2-3 inches LONGER than my Height so Wife laughed and said that I am an Ape!

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