Leonardo Proportions Calculator
Da Vinci drew the "ideal" human as a geometry problem. Grab a tape measure and see how you compare.
Measure yourself against the Vitruvian Man
What Leonardo actually drew
Around 1490, Leonardo da Vinci sketched a man inscribed in both a circle and a square, illustrating the proportions described by the Roman architect Vitruvius fifteen centuries earlier. The square's claim: arm span equals height — stretch your arms and you fit a perfect square. The drawing layers dozens more ratios: the body stands 8 head-heights tall (Vitruvius said the face is one-tenth of height), the navel centers the circle, the foot is one-sixth of height. It was anatomy, geometry, and philosophy on one page — the Renaissance conviction that the human body encodes the proportions of the cosmos.
How real bodies measure up
Population data says Leonardo chose well: average arm-span-to-height ratios cluster near 1.0, typically running 1.0–1.04 in men and 0.99–1.01 in women. The outliers are interesting — elite swimmers and boxers trend "wingspan-positive" (Michael Phelps famously carries a 6'7" span on a 6'4" frame, ratio ≈ 1.04), while gymnasts trend compact. The 8-heads ideal is actually generous: most adults measure 7–7.5 heads, which is why fashion illustration deliberately stretches figures to 8+ — Leonardo's ideal became art's default flattery.
The fun and the fine print
Measure honestly: stand against a wall for height; for span, arms straight out at shoulder height, middle fingertip to middle fingertip (a doorframe and a pencil help). None of this grades your body — deviation from a 530-year-old drawing means nothing for health (though medicine does use span-vs-height clinically: a ratio well above ~1.05 is one screening sign in connective-tissue evaluations, which only a doctor can interpret). Mostly, this is the rare calculator whose answer is a Renaissance compliment. Enjoy it.
Frequently asked questions
Is arm span really supposed to equal height?
That's the Vitruvian square, and population averages land remarkably close to 1.0. A few percent either way is completely normal variation, not a flaw.
What does it mean if my arms are much longer than my height?
Usually just genetics — and an advantage in swimming, boxing, climbing, and deadlifting. Ratios well above ~1.05 are one of several screening measurements doctors use for certain connective-tissue conditions; a number alone diagnoses nothing.
Why does art use 8 heads if real people are 7.5?
Because 8 heads reads as heroic on the page. Leonardo drew an ideal; fashion and comic illustration pushed it further. Real, healthy humans average shorter in head-units — the camera and the sketchpad simply flatter differently.
How do I measure arm span accurately?
Arms straight out at shoulder height against a wall, palms forward. Mark each middle fingertip and measure the line. A helper makes it accurate; a doorframe makes it possible alone.