Body Type Calculator

Somatotype is a way of describing physique using three components: ectomorphy (linearity, a long narrow build), mesomorphy (muscle and bone robustness) and endomorphy (relative fatness). The psychologist William Sheldon devised it in the 1940s. Most people are a blend, which is why the proper method gives a rating on all three rather than a single label.

The one part this page can measure properly

The method in use today is Heath-Carter. Endomorphy comes from three skinfolds and mesomorphy from bone breadths and limb girths, which needs calipers and practice. Ectomorphy needs only height and weight, through the height-weight ratio (HWR):

HWR = height (cm) ÷ cube root of weight (kg)

• HWR 40.75 or more: ectomorphy = 0.732 × HWR − 28.58
• HWR between 38.25 and 40.75: ectomorphy = 0.463 × HWR − 17.63
• HWR 38.25 or less: ectomorphy = 0.1

Carter and Heath (1990) read any component on a scale where ½ to 2½ is low, 3 to 5 moderate, 5½ to 7 high and 7½ or more very high.

What the rest of the reading uses

The frame thresholds:

where ratio = height ÷ wrist circumference, both in the same unit. These are the same bands as the body frame calculator.

How the page names a type: a high ectomorphy rating means a linear build, an ectomorph. A low rating means you are heavy for your height, and that weight is either muscle or fat. Height and weight cannot tell those apart, so the body fat box decides between mesomorph and endomorph. Leave it blank and the page says plainly that it cannot choose.

Worked example

A man 70 inches tall (177.8 cm) weighing 175 lbs (79.4 kg), with a 7.0 inch wrist and 15% body fat.

• HWR = 177.8 ÷ 4.298 = 41.37, so ectomorphy = 0.732 × 41.37 − 28.58 = 1.7, low
• Frame ratio = 70 / 7.0 = 10.0, medium for a man
• 15% body fat sits in the ACE fitness band for men (14 to 17%)

Result: mesomorph. He is heavy for his height and lean, so the weight is muscle. At 26% body fat the same height and weight would read as endomorph.

How much should you believe this?

Less than most fitness sites will tell you. Sheldon’s original work was constitutional psychology: he claimed body type predicted temperament and criminality, and it collected the Ivy League posture photographs that became a genuine scandal. That side of it is discredited and nobody defends it now. Heath-Carter is a legitimate way to describe a physique, but it describes what you look like today rather than predicting how you will respond to training.

There is no good evidence that a lean person needs a fundamentally different program from a broad one. The diet advice attached to body types is the weakest part. In the DIETFITS trial (Gardner and colleagues, 2018), 609 adults on a healthy low-fat or a healthy low-carb diet lost about the same weight over a year, and neither their genes nor their insulin response predicted which diet suited them. Progressive overload, enough protein and a calorie intake pointed at your goal do the work.