Ideal weight
Lorentz, Devine, Robinson and BMI range: 4 answers compared.
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Four formulas beat one magic number
The “ideal weight” doesn’t exist as a single number: every historical formula gives a different answer. This tool computes Lorentz, Devine and Robinson side by side, shows their average and adds the only official reference: the weight range matching a healthy BMI (18.5–24.9) per the WHO.
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Enter your height
In centimetres — the only measurement needed.
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Pick your sex
Coefficients differ to reflect average body composition.
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Compare
The average gives the benchmark; the table shows how the methods spread.
Example: 175 cm, man
| Method | Result |
|---|---|
| Lorentz | 68.8 kg |
| Devine | 70.5 kg |
| Robinson | 68.9 kg |
| Healthy BMI range | 56.7 – 76.3 kg |
These formulas are statistical reference points, not a medical target: they ignore muscle, frame and age. For any weight journey, talk to a healthcare professional.
Frequently asked questions
Why four methods rather than one?
Each formula has its history and biases: Lorentz (1929) is harsh on tall people, Devine (1974) was created for drug dosing, Robinson (1983) slightly corrects it. Comparing them gives an honest range rather than a falsely precise number.
Which formula is the most reliable?
None is “true”: they all ignore muscle mass, frame size and age. The healthy BMI range (18.5–24.9) is the WHO reference and the most used in public health — it is the most relevant bracket for most people.
Does ideal weight work for athletes?
Poorly: a muscular rugby player often exceeds every formula while being in excellent health, because muscle weighs more than fat at equal volume. For athletes, body fat percentage is a far better indicator — our dedicated tool computes it.
Why do men’s and women’s values differ?
At equal height, average body composition differs: more muscle mass in men, which the coefficients reflect (Lorentz divides by 4 for men, 2.5 for women; Devine starts at 50 kg versus 45.5 kg).