Methodology
Every ratio on this site is a division of two measurements. This page lists the formulas, the measurement definitions, the reference source and the limit of each number.
bodyproportion.com expresses body proportions as ratios — heads tall, leg-to-height, torso-to-leg, shoulder-to-hip and more — for clothing fit and figure drawing, using published reference ranges.
What the calculator does
It converts the measurements you enter to centimetres, divides them according to the formulas below, and compares the result with a reference band. The calculation runs in your browser. The page does not send the numbers to a server, does not write them to localStorage, and does not put them in the URL.
It does not classify body shape, diagnose health, score attractiveness or recommend a garment size. The only health-adjacent numbers are waist-to-hip and waist-to-height; both are labelled as reference points.
The eight formulas
| Ratio | Formula | Reference band |
|---|---|---|
| Heads tall | height ÷ head height | 6.5–8.5 |
| Leg-to-height | inseam ÷ height | 0.43–0.48 |
| Sitting height ratio | sitting height ÷ height | 0.48–0.55 |
| Shoulder-to-hip | shoulder circumference ÷ hip circumference | 0.85–1.15 |
| Shoulder-to-waist | shoulder circumference ÷ waist circumference | 1.2–1.8 |
| Arm span-to-height | arm span ÷ height | 0.9–1.05 |
| Waist-to-hip | waist circumference ÷ hip circumference | 0.65–0.85 |
| Waist-to-height | waist circumference ÷ height | 0.4–0.49 |
Measurement definitions
| Input | Definition used here |
|---|---|
| Height | Standing height without shoes, feet together, head neutral. |
| Head height | Crown of the head to the chin; no hair volume, no neck. |
| Inseam | Floor to the crotch, without shoes, feet together, tape vertical. |
| Sitting height | Seat surface to the top of the head, back straight, feet flat. |
| Shoulder circumference | Around the widest point of the shoulders and upper back, arms down, tape level. |
| Waist | Narrowest point of the torso, relaxed exhale, tape level. |
| Hip | Fullest point of the hips and seat, feet together, tape level. |
| Arm span | Fingertip to fingertip, arms horizontal, shoulders relaxed. |
These definitions matter. A “leg length” measured from the hip bone, or a “shoulder width” measured as a straight line, will not produce the same ratio. The site uses the definitions above on every page.
Reference bands: what kind of number is it?
| Ratio | Type of reference | Source |
|---|---|---|
| Heads tall | Artistic convention + measured sample | 7.5/8/8.5 canon; 2020 Vitruvian study |
| Leg-to-height | Common range | ~45%, 43–48%; definitions vary |
| Sitting height ratio | Population reference | Pheasant (1986); 0.48–0.55 |
| Shoulder-to-hip | Descriptive | No universal target; near 1.00 = similar circumferences |
| Shoulder-to-waist | Training convention | 1.618 popular benchmark; no clinical standard |
| Arm span-to-height | Measured sample | 0.96 men / 0.92 women (2020) |
| Waist-to-hip | Clinical reference point | WHO: 0.85 women / 0.90 men |
| Waist-to-height | Public guidance | NICE: keep under 0.50; bands vary slightly |
Canon vs measured
The eight-head canon is an artistic choice. It is useful for drawing, but it is not a population average. The 2020 Vitruvian Man re-analysis found mean head height of 0.14 of stature for men and 0.15 for women — about 7.1 and 6.7 heads. The site shows both so you can choose the reference that fits your purpose.
Limits
- Definitions vary. Leg length and shoulder width are the two most common sources of disagreement between calculators.
- Samples are specific. The 2020 arm span and head height means come from a US Air Force population, not a global average.
- Health ratios are reference points. Waist-to-hip and waist-to-height do not diagnose health, and thresholds differ slightly between guidelines.
- A ratio is not a person. The calculator describes relationships between measurements; it does not rank bodies.
Method questions
Which numbers are measured and which are artistic conventions?
The measured data comes from the 2020 Vitruvian Man re-analysis and the sitting-height literature. The 7.5/8/8.5-head canon and the 1.618 shoulder-to-waist benchmark are artistic or training conventions. The method page labels each one.
How are the reference bands chosen?
They come from the cited source where a source exists (sitting height, waist-to-hip, waist-to-height, arm span), or from the common range in the literature (heads tall, leg-to-height). The shoulder-to-hip band is descriptive, not a target.
Why is there no single “ideal” set of proportions?
Because human proportions vary by population, age, sex and measurement definition, and because “ideal” is a cultural and artistic choice rather than a measurement. The calculator gives you the number and its reference; it does not grade the body.
Sources
- Revisiting Vitruvian Man (2020). Revisiting Leonardo da Vinci’s Vitruvian Man Using Contemporary Measurements. PMC7284298 (2020). https://pmc.ncbi.nlm.nih.gov/articles/PMC7284298/ 63,623 men and 1,385 women from US Air Force body-scan data. Head height 0.14/0.15 of stature; arm span 0.96/0.92; shoulder width 0.24/0.25.
- Bogin & Varela-Silva (2010). Bogin, B., & Varela-Silva, M. I. (2010). Leg length, body proportion, and health: a review with a note on beauty. International Journal of Environmental Research and Public Health, 7(3), 1047–1075. https://pmc.ncbi.nlm.nih.gov/articles/PMC2872302/ Explains why leg length has no single definition: inseam, iliac height and subischial leg length give different ratios.
- Pheasant (1986) / UNU. Pheasant, S. (1986). Bodyspace: Anthropometry, Ergonomics and the Design of Work. Cited in the UNU open chapter “The effect of shape”. https://archive.unu.edu/unupress/food2/UID10E/UID10E06.HTM Sitting-height-to-stature ratios: about 0.52 European, 0.51 African, 0.53–0.54 Asian; 0.48–0.55 across populations.
- WHO waist circumference and waist–hip ratio. World Health Organization. Waist circumference and waist–hip ratio: report of a WHO expert consultation (2008). https://www.who.int/publications/i/item/9789241501491 Waist–hip ratio reference points of 0.85 for women and 0.90 for men.
- NICE (2022) waist-to-height guidance. National Institute for Health and Care Excellence (2022). Keep your waist to less than half your height. https://www.nice.org.uk/guidance/cg189/resources The “less than half your height” public guidance; bands differ slightly between guidelines.
- Artists Network: 7.5-head figure. Artists Network. Drawing the Proportions of the Human Body. Ameral, 2010. https://www.artistsnetwork.com/art-techniques/drawing-proportions-human-body-ameral/ A 7.5-head figure is the standard used in many realist schools; most adults are about 7–7.5 heads.
- Practical Drawing: the eight-head canon. Practical Drawing, Chapter 2 (Wikisource). The classical canon of eight heads and its use in idealised figures. https://en.wikisource.org/wiki/Practical_Drawing/Chapter_2 The eight-head canon is an artistic convention for dignity and grandeur, not a population average.