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Body Type Calculator

Which of the three classic body types your measurements resemble, from Heath-Carter ectomorphy, fat-free mass index and body fat — with the weak science labelled.

Body Type Calculator: with the default inputs, closest of the three descriptions is Mesomorph-leaning — more lean mass for your height than average.

ft
in
Try an example
Somatotyping is a description of your current measurements, not a fixed type you were born with and not a prediction of anything. Body composition moves with training and food; the label here can change in a year.
There is no good evidence that body type determines the diet or training programme you should follow. Claims that ectomorphs need more carbohydrate or endomorphs must avoid them are marketing, not physiology.
Closest of the three descriptions
Mesomorph-leaning — more lean mass for your height than average
Heath-Carter ectomorphy rating
2.3
Fat-free mass index
19.5
Estimated body fat
17.4%
Fat-free mass
136.2 lb
Height-to-weight ratio
42.19
Waist-to-height ratio
0.49
Assumptions
  • Ectomorphy is the exact Heath-Carter component from height and weight. The other two components are proxies — fat-free mass index for mesomorphy and Navy-method body fat for endomorphy — because real Heath-Carter ratings need skinfold calipers and bone-breadth calipers.
  • Body fat comes from the US Navy circumference method with the Siri equation, which is typically within about 3–4 percentage points of a laboratory measurement and can be further off for very lean or very heavy people.
  • The reference mid-points used to pick a dominant component are this calculator's stated convention, drawn from published population figures. They are not clinical cut-offs.
  • Somatotype describes current shape. It is not inherited, fixed, or predictive of how you respond to diet or training.
  • This is an estimate and a description, not a diagnosis or a health assessment.
Each component against its reference mid-point (1.00 = average)
00.51Ectomorphy (linearity)Mesomorphy proxy (FFMI)Endomorphy proxy (body fat)
Ratio to reference
What each measurement is and where the reference comes from
ComponentYouReferenceSource
Ectomorphy (linearity)2.32.5Heath-Carter somatotype, from height ÷ ∛weight
Fat-free mass index19.519.5Kouri et al. (1995), non-steroid-using adults
Body fat %17.4%21%Mid-point of the ACE 'average' band
Waist-to-height ratio0.49under 0.50Standard public-health guide; the most evidence-backed number here

The reference mid-points are this calculator's stated convention for deciding which component stands out. They are not clinical cut-offs and nothing here diagnoses anything.

Math verified by automated testsUpdated 2026-09-093 sources cited

How this is worked out

The formula

HWR = height (cm) ÷ ∛weight (kg)

Heath-Carter ectomorphy:
  HWR ≥ 40.75            → 0.732 × HWR − 28.58
  38.25 < HWR < 40.75    → 0.463 × HWR − 17.63
  HWR ≤ 38.25            → 0.1

Body fat: US Navy circumference method → Siri equation, 495 ÷ density − 450
Fat-free mass index = weight × (1 − body fat) ÷ height (m)²

Open How it’s calculated above to see this worked through with your own numbers.

What you enter

Height
A number.in ft, in, cm, m · from 3 to 8.5 · defaults to 5.8333
Weight
A number.in lb, kg, st · from 40 to 1000 · defaults to 165
Sex
Choose one of 2 options.Male · Female
Neck circumference
Just below the larynx, tape sloping slightly down at the front.in in, cm · from 8 to 30 · defaults to 15
Waist circumference
Men: at the navel. Women: at the narrowest point.in in, cm · from 15 to 80 · defaults to 34
Hip circumference
Widest point around the buttocks. Used for the female body-fat estimate only.in in, cm · from 20 to 80 · defaults to 39

What you get back

Closest of the three descriptionsmain answer
Heath-Carter ectomorphy rating
The linearity component of the somatotype, on a scale that usually runs 0.1 to about 9.
Fat-free mass index
Lean mass ÷ height². A muscularity measure that adjusts for size.
Estimated body fat
US Navy circumference method.
Fat-free mass
Height-to-weight ratio
Height in cm ÷ the cube root of weight in kg — the input to ectomorphy.
Waist-to-height ratio
Under 0.5 is the usual public-health guide.

What this assumes

  • Ectomorphy is the exact Heath-Carter component from height and weight. The other two components are proxies — fat-free mass index for mesomorphy and Navy-method body fat for endomorphy — because real Heath-Carter ratings need skinfold calipers and bone-breadth calipers.
  • Body fat comes from the US Navy circumference method with the Siri equation, which is typically within about 3–4 percentage points of a laboratory measurement and can be further off for very lean or very heavy people.
  • The reference mid-points used to pick a dominant component are this calculator's stated convention, drawn from published population figures. They are not clinical cut-offs.
  • Somatotype describes current shape. It is not inherited, fixed, or predictive of how you respond to diet or training.
  • This is an estimate and a description, not a diagnosis or a health assessment.

About this calculator

Before you use this: somatotyping has weak scientific support, and it is worth knowing why before you take a label from it.

Where "body type" came from

William Sheldon published the ectomorph / mesomorph / endomorph scheme in the 1940s, based on photographs of several thousand college men. The classification itself was descriptive and not unreasonable. What Sheldon built on top of it was not: he claimed body shape predicted temperament, intelligence and criminal tendency, with correlations so implausibly high that later researchers concluded he had rated the photographs and the personalities himself. That part of the work is discredited, and the photographs were collected in circumstances that would never pass an ethics board today.

Barbara Heath and Lindsay Carter salvaged the useful half in the 1960s. Their anthropometric somatotype is a real measurement method — three numbers from skinfolds, bone breadths and girths — still used in sports anthropometry to describe athlete populations. It describes shape. It does not explain metabolism, predict how you respond to training, or tell you what to eat.

What this calculator actually does

It measures three things you can get with a tape and a scale, and tells you which stands out:

  • Ectomorphy is the genuine Heath-Carter component, computed exactly, from your height divided by the cube root of your weight. It measures linearity: how long and light you are for your size.
  • Fat-free mass index stands in for mesomorphy. It is lean mass divided by height squared — a real, published muscularity measure, not a somatotype rating.
  • Body fat percentage from the US Navy tape method stands in for endomorphy, which properly needs skinfold calipers most people do not own.

Two of the three are therefore proxies, clearly labelled. The reference mid-points used to decide which component "wins" are this calculator's stated convention, drawn from published population figures — not diagnostic thresholds.

What it is honestly useful for

Three things. It gives you a baseline body-composition snapshot you can repeat in three months. It shows you which of the three dimensions is actually distinctive about your build, which is more informative than a single label. And it puts a waist-to-height ratio in front of you, which is the one number on the page with real predictive evidence behind it.

What it is not useful for

Choosing a diet. Choosing a training split. Explaining why you have not made progress. Deciding what you are capable of. There is no good trial evidence that "ectomorphs" need more carbohydrate, that "endomorphs" must avoid it, or that any of this predicts training response — the studies that do predict response point at training history, sleep, protein intake and consistency instead. If a coach or a supplement page is segmenting you by body type, they are selling something.

Finally: your build is not a moral category, and a shifted label is not an achievement or a failure. Use the numbers as a baseline and ignore the noun.

Frequently asked questions

Is body type real science?

Partly. The Heath-Carter method is a real anthropometric measurement used in sports science to describe populations. Sheldon's original claim that body shape predicts personality and behaviour is discredited, and nothing supports body type as a guide to diet or training.

Can you change your body type?

You can change two of the three components substantially. Muscle and fat both respond to training and food. Skeletal proportions — how long your limbs are relative to your torso — do not change in adults, and that is what the ectomorphy rating mostly reflects.

Should ectomorphs eat differently from endomorphs?

There is no trial evidence for it. Calorie needs scale with body size and activity, protein needs with lean mass, and both are already covered by ordinary calculators. Body type adds nothing on top.

Why does this need my neck and waist?

To estimate body fat with the US Navy circumference method, which stands in for the endomorphy component. Proper Heath-Carter endomorphy needs three skinfolds and a set of calipers.

What if I come out balanced?

That is the most common result and it is not a cop-out. It means no single dimension is unusual for your size — which is true of most people, and the reason a three-word taxonomy was never going to carry much information.

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