Body Type Calculator

The three body types, explained honestly

The somatotype idea — ectomorph, mesomorph, endomorph — was coined by psychologist William Sheldon in the 1940s, and it's worth saying up front that the science around his original claims aged badly. What survived is the useful part: as plain descriptions of build, the three categories map onto things people genuinely notice about themselves. Ectomorphs are narrow-framed and struggle to gain weight of any kind. Mesomorphs carry muscle easily and respond fast to training. Endomorphs have wider frames and gain — muscle and fat alike — without much trying.

Almost nobody is a pure type. Think of it as a blend — a scale with three sliders rather than three boxes — and this calculator estimates where your sliders sit, using bone measurements that don't change with your diet.

Why wrists and ankles?

Weight fluctuates and muscle can be built, but the circumference of your wrist is nearly all bone and tendon — it's an honest, diet-proof signal of frame size. The calculator compares your wrist and ankle to your height: relative to a 170 cm body, a slender wrist points ectomorph, a thick one endomorph, and the middle band mesomorph. It's the same logic tailors and orthopaedists have used informally forever.

It's an estimate, and it measures your frame, not your fitness. What you build on that frame is entirely up to training and food — which is exactly why the label should inform your plan, never limit it.

What your body type means for training and eating

The practical differences are mostly about starting conditions, not ceilings. Narrow-framed people trying to gain muscle usually need more calories than they expect — a real surplus, tracked honestly, because their appetite lies low. Wider-framed people cutting fat benefit from the opposite discipline: their appetite runs ahead of their burn, so structure (protein-forward meals, planned calories) does the heavy lifting. Natural mesomorphs mostly need to avoid coasting on genetics.

Whatever your blend, the tools are the same. The calorie calculator sets your intake for gaining or cutting, the macro calculator splits it sensibly, and the body fat calculator tracks whether the plan is actually changing your composition.

Frequently asked questions about body types

Sources and further reading

• Ryan-Stewart H et al. — The influence of somatotype on anaerobic performance (PLoS One, 2018)
• American Council on Exercise — Training across body types

This page is for general information only. Body type is a descriptive framework — it doesn't limit what training and nutrition can achieve.