Ideal Weight Calculator

How it works

"Ideal body weight" (IBW) is a clinical concept used most often for medication dosing and ventilator settings, not as a personal goal. There is no single perfect formula. We show four classic formulas plus the WHO healthy-BMI range so you can see how much they vary — usually within a few kilograms of each other.

The Devine formula (1974) is the most cited in clinical pharmacology: 50 kg + 2.3 kg per inch over 5 feet for men, 45.5 + 2.3 for women. Robinson (1983) revised the constants slightly. Miller (1983) reduced the per-inch increment to 1.41/1.36, producing slightly lower IBWs. Hamwi (1964) used 2.7/2.2 per inch, producing higher IBWs. None was developed for body-image use; all were developed for medication dosing in hospital settings.

For most personal-fitness purposes, the WHO healthy-BMI range (18.5–24.9) is a more useful target. It defines a band of weights for your height that are associated with the lowest mortality risk in epidemiological studies. Any weight in that range is reasonable; the formulas above are all near the middle of it.

Body composition matters more than absolute weight. A 175 cm muscular man might weigh 80 kg with low body fat and excellent metabolic markers, while another at 70 kg with high body fat could be at higher cardiovascular risk despite weighing less. Use these formulas alongside body fat percentage, fitness markers, and how you feel — not as the sole goal.

If you have a specific medical reason to know your IBW (chemotherapy dosing, anesthesia, ventilator settings), use the formula your provider specifies. For weight-loss goals, set a target somewhere in the healthy BMI range, not a single numeric "ideal".