Ideal body weight (IBW) is most commonly estimated using the Devine formula: for men, 50 kg + 2.3 kg per inch over 5 feet; for women, 45.5 kg + 2.3 kg per inch over 5 feet. A 5'10" man has an IBW of ~166 lbs; a 5'6" woman's is ~130 lbs. These are clinical reference points — not rigid personal targets.
Ideal body weight is a concept developed for medication dosing and clinical nutrition — not originally a fitness goal. But the formulas are useful as one data point among several when evaluating a healthy weight range. Unlike BMI, IBW accounts for height precisely and avoids the "overweight at any muscle mass" problem that trips up athletic people.
Why BMI Falls Short as a Personal Target
BMI divides weight by height squared — a ratio that treats a 160-lb bodybuilder and a 160-lb sedentary person identically. BMI does not distinguish muscle from fat, does not account for where fat is distributed, and has known biases by race and age. The World Health Organization acknowledges these limitations explicitly. IBW formulas are not perfect either, but they provide a narrower, height-specific target rather than a wide statistical range.
Common Ideal Body Weight Formulas
- •Devine formula (1974, most common clinically): Men: 50 kg + 2.3 kg × (inches over 60); Women: 45.5 kg + 2.3 kg × (inches over 60)
- •Robinson formula (1983): Men: 52 kg + 1.9 kg per inch over 5 ft; Women: 49 kg + 1.7 kg per inch over 5 ft
- •Hamwi formula (1964): Men: 106 lbs + 6 lbs per inch over 5 ft; Women: 100 lbs + 5 lbs per inch over 5 ft
- •Miller formula (1983): Men: 56.2 kg + 1.41 kg per inch over 5 ft; Women: 53.1 kg + 1.36 kg per inch over 5 ft
- •Most clinicians use a range: IBW ± 10% to account for frame size and body composition differences
Calculate Your Ideal Body Weight
How to Interpret Your Result
Your IBW result is a reference point, not a goal you must hit. Consider: if your current weight is within 10% of your IBW, most health metrics suggest you are in a reasonable range. If you are significantly above, the direction matters more than the specific number — trending toward a healthier weight over months yields most of the health benefits before you reach a formula's exact output. If you are significantly below your IBW (especially combined with low body fat), that is a different clinical concern entirely.
The Role of Body Composition
Two people at exactly the same height with the same IBW can have wildly different health profiles depending on their body fat percentage and muscle mass. A 5'8" woman at 140 lbs with 30% body fat has a different metabolic health picture than a 5'8" woman at 140 lbs with 22% body fat. If you are serious about body composition, add a body fat measurement (DEXA scan, hydrostatic weighing, or even a handheld bioimpedance device) rather than relying on weight alone. — CDC National Health Statistics
Frame size matters. People with smaller frames (narrow wrists, smaller bone structure) typically sit toward the lower end of the IBW range; larger-framed people sit toward the upper end. A quick proxy: wrap your thumb and middle finger around your wrist. If they overlap, you likely have a small frame; if they do not meet, you likely have a large frame.