Method
How the calculator works and how to measure
Everything is worked out in your browser from simple ratios. Here is exactly what the calculator does.
How to measure
- Height: without shoes, standing straight against a wall.
- Weight: in light clothing, ideally at the same time of day.
- Bust or chest: around the fullest part, with the tape level under the arms.
- Waist: around the narrowest part of your torso, usually just above the belly button. Stand relaxed and breathe out normally.
- Hips: around the widest part of your bottom, feet together.
Measure with a soft measuring tape, snug but not tight, over light clothing or bare skin.
Body shape rules
The calculator compares your measurements as ratios, so the result is the same in centimetres or inches and does not depend on your size. The rules are checked in this order; the first one that fits wins. They are a ratio-based simplification inspired by the Female Figure Identification Technique (Simmons, Istook and Devarajan, 2004), with an added apple rule.
| Shape | Women (bust, waist, hips) | Men (chest, waist, hips) |
|---|---|---|
| 1. Apple | Waist ≥ 90% of hips and ≥ 90% of bust | Waist ≥ 95% of hips and ≥ 95% of chest |
| 2. Pear | Hips ≥ 5% wider than bust | Hips ≥ 5% wider than chest |
| 3. Inverted triangle | Bust ≥ 5% wider than hips | Chest ≥ 10% wider than hips, or ≥ 25% wider than waist |
| 4. Hourglass | Waist ≤ 75% of bust or hips | Not used |
| 5. Rectangle | Everything else | Everything else |
Without a bust or chest measurement the calculator cannot compare your top and bottom half. It still checks the apple rule, then shows a provisional result: pear (or hourglass) if the waist is 75% of the hips or less, otherwise rectangle, and names the likely alternatives.
Somatotype: a simple estimate
Somatotypes (ectomorph, mesomorph, endomorph) come from the Heath-Carter method, which properly needs skinfold and bone measurements. We only have height, weight and waist, so this is a rough lean, clearly labelled as an estimate:
- Endomorph if your waist-to-height ratio is 0.53 or more.
- Ectomorph if your Heath-Carter ectomorphy score is 3.5 or more. That score comes from the height-weight ratio: height in cm divided by the cube root of weight in kg.
- Mesomorph otherwise: a balanced, medium build.
The ratios
- Waist-to-hip ratio = waist ÷ hips. The World Health Organization uses 0.85 or more for women and 0.90 or more for men as a sign of substantially increased risk of metabolic complications.
- Waist-to-height ratio = waist ÷ height. A common guideline is to keep your waist below half your height (under 0.5). NICE classes 0.5 to 0.59 as increased and 0.6 or more as high.
- BMI = weight in kg ÷ (height in m)². Adult categories: under 18.5 underweight, 18.5 to 24.9 healthy weight, 25 to 29.9 overweight, 30 or more obesity.
All results are estimates for clothing and general interest. They are not a diagnosis and not medical advice. For health questions, talk to a doctor or nurse.
Sources
- World Health Organization (2011). Waist circumference and waist-hip ratio: report of a WHO expert consultation.
- NICE guideline NG246. Overweight and obesity management (waist-to-height ratio).
- CDC. Adult BMI categories.
- Simmons K, Istook C, Devarajan P (2004). Female Figure Identification Technique (FFIT) for apparel. Journal of Textile and Apparel, Technology and Management 4(1).
- Carter JEL (2002). The Heath-Carter anthropometric somatotype: instruction manual.