Ideal weight
Calculate your target weight in 10 seconds. The simulator combines the 3 reference medical formulas — Lorentz, Creff and Devine — and shows the average for a realistic health goal.
* Theoretical indicative weight. Does not replace professional medical advice.
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How to calculate your ideal weight reliably?
Your ideal weight (or target weight) is not an absolute truth; it is a statistical health benchmark. Unlike the BMI which gives you a broad range, ideal weight formulas aim at a precise, numeric health target based on your own physiology.
The 3 reference calculation methods
Lorentz (1929)
The most widely used in France. Based on the ratio between height and gender. Simple and effective, a bit strict for very tall people.
Creff
The most comprehensive. Adds two physiological parameters: age and bone structure (fine, normal, broad). Matches reality better.
Devine (1974)
The Anglo-Saxon reference. Initially designed for drug dosage, it offers a recognized clinical reliability.
Why average the 3 formulas?
Because every mathematical formula has its biases. By averaging Lorentz, Creff and Devine, the calculator smooths the extremes. You get a target weight that is healthier, more realistic and easier to achieve day to day.
How to estimate your body type?
The wrist test (Rohrer method):
- Fine body type — your thumb and middle finger overlap broadly when wrapping your wrist.
- Normal body type — your thumb and middle finger just touch, without overlapping.
- Broad body type — your thumb and middle finger do not touch.
Medical limits to keep in mind
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Muscle mass: a kilo of muscle is denser than a kilo of fat. An athlete will weigh well above their theoretical ideal weight while being perfectly healthy.
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Pregnancy: this tool is not suitable for pregnant women. Consult your doctor for personalized follow-up.
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Indicative only: this calculation never replaces the advice of a health professional (doctor, dietitian, nutritionist).
FAQ
What is the difference between BMI and ideal weight?
The Body Mass Index (BMI) gives you a health "zone" (e.g. "normal weight between 60 kg and 75 kg"). Ideal weight formulas target a specific number down to the kilo (e.g. "your target weight is 67 kg"). Both tools complement each other to monitor your balance.
Which ideal weight calculation formula is the most reliable?
Medically, the Creff formula is often considered the most relevant. It's the only equation that adjusts weight by accounting for natural aging (age) and the thickness of your bone structure (body type).
Ideal weight for women vs men: is the calculation different?
Yes, absolutely. The Lorentz and Devine formulas use different mathematical constants depending on gender, because the natural distribution of muscle and fat mass differs between men and women.
Why does my target weight seem so low?
These historical formulas compute a very lean and optimized weight. If you do a lot of sports or have a developed muscle mass, this calculation will seem underestimated. Use this result as a health benchmark, not as an absolute injunction.
Is this tool suitable for everyone?
No. It is not suitable for pregnant women, children and teenagers under 15, or elite athletes whose muscle mass completely skews the calculation. In those cases, ask a health professional for advice.
