Ape Index Calculator — Arm Span vs Height
Measure your ape index: the difference between your arm span and your height. A positive index means your arms are longer than your height, which is considered advantageous in rock climbing, swimming, basketball, and boxing.
Units
cm
cm
Arm span minus height — positive means longer arms
- 1
Ape ratio (span ÷ height)
182 ÷ 178 = 1.022 - 2
Ape index (span − height)
182 − 178 = 4Positive value means arm span exceeds height.
How does this calculator work?
Ape Index = Arm Span − Height (same units). A positive index means arms are longer than height; negative means shorter. The ape ratio (arm span ÷ height) is the dimensionless equivalent — 1.0 is neutral. Typically ±5 cm in the general population; climbers and swimmers often have +5 to +15 cm.
Formula
How this is calculated
Leonardo da Vinci's Vitruvian Man illustrates a person whose arm span equals their height — a ratio of 1.0. In reality, arm span and height are closely correlated but not equal; the difference is called the ape index (also "ape factor" or "wingspan difference"). A positive ape index (arm span > height) is common and tends to be beneficial in sports requiring long reach, such as rock climbing (longer reach between holds), swimming (greater propulsion), and basketball (wider defensive coverage).
The ape index is simply arm span minus height, measured in the same unit. The ape ratio (arm span divided by height) normalises the difference across body sizes — a ratio greater than 1.0 indicates longer arms, less than 1.0 indicates shorter arms. Both measures are interchangeable; the index is more intuitive ("my arms are 4 cm longer than I am tall") while the ratio is dimensionless and easier to compare across people of very different sizes.
Measurement tips: measure arm span with arms outstretched horizontally at shoulder height from the tip of the left middle finger to the tip of the right middle finger. Stand against a wall for accuracy. Height should be without shoes. Population studies typically find the average ape index close to zero with a standard deviation of about 5 cm, so an index of +10 cm or more is genuinely notable.
Frequently asked questions
Positive indices (arm span longer than height) are generally favoured in rock climbing because you can reach farther between holds. Elite climbers often have indices in the +5 to +15 cm range, but technique, strength, and flexibility matter far more than reach. A small negative index does not preclude elite climbing.
No. Arm span (also called wingspan) is the absolute measurement from fingertip to fingertip. The ape index is the difference between arm span and height, telling you how much your reach differs from your stature. An ape ratio of 1.05 means your arm span is 5% longer than your height.
The ape index is determined by skeletal proportions and is largely fixed after growth is complete in your late teens or early twenties. Weight, posture, and flexibility do not change your arm span or height meaningfully, so the index stays essentially constant through adulthood.
Also known as
TG we-Calculate Editorial Team. (2026). Ape Index Calculator — Arm Span vs Height [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/ape-index-calculator
TG we-Calculate Editorial Team. "Ape Index Calculator — Arm Span vs Height." TG we-Calculate. 2026. https://we-calculate.com/calculator/ape-index-calculator.
TG we-Calculate Editorial Team, "Ape Index Calculator — Arm Span vs Height," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/ape-index-calculator
@misc{wecalculate_ape_index_calculator, title = {Ape Index Calculator — Arm Span vs Height}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/ape-index-calculator}}, year = {2026}, note = {TG we-Calculate} }
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