"Ideal body weight" sounds simple — surely there's one number that represents the healthiest weight for a given height? In practice, five major formulas give meaningfully different results, and none of them fully account for body composition, frame size, age, or muscle mass. Here's how to use them intelligently.
The Five Major Ideal Body Weight Formulas
1. Hamwi Formula (1964)
Originally developed for clinical use (medication dosing):
- Men: 48 kg + 2.7 kg per inch over 5 feet
- Women: 45.5 kg + 2.2 kg per inch over 5 feet
2. Devine Formula (1974)
Developed for creatinine clearance calculations — now the most widely used clinically:
- Men: 50 kg + 2.3 kg per inch over 5 feet
- Women: 45.5 kg + 2.3 kg per inch over 5 feet
3. Robinson Formula (1983)
- Men: 52 kg + 1.9 kg per inch over 5 feet
- Women: 49 kg + 1.7 kg per inch over 5 feet
4. Miller Formula (1983)
- Men: 56.2 kg + 1.41 kg per inch over 5 feet
- Women: 53.1 kg + 1.36 kg per inch over 5 feet
5. BMI-Based Ideal Weight
The "healthy" BMI range (18.5–24.9) implies an ideal weight range for a given height. For a 5'10" male, this spans 58–78 kg — a 20 kg range that illustrates why a single "ideal" number is necessarily an oversimplification.
All five formulas were developed primarily for pharmaceutical and clinical dosing — not as personal fitness targets. A muscular 90 kg athlete at 10% body fat may be far "above" their ideal body weight by every formula, yet be in exceptional health. Body composition matters far more than scale weight.
The Limitations of Ideal Body Weight
- Doesn't account for muscle mass (athletes will always appear "overweight")
- Doesn't account for bone density or frame size
- Formulas were derived largely from white European populations — may be less accurate across ethnic groups
- None adjust for age (muscle mass naturally decreases with age)
A More Useful Approach
Rather than chasing a specific ideal weight number, track:
- Body fat percentage — directly measures fat vs lean mass
- Waist circumference — strongly predicts metabolic risk independently of weight
- Waist-to-height ratio — keep your waist under half your height for low cardiometabolic risk
- How you feel and perform — energy, strength, sleep quality are the real indicators of optimal weight
Calculate Your Ideal Body Weight
Use our ideal body weight calculator to see your result across all major formulas side by side.
Open IBW Calculator →The Bottom Line
Ideal body weight formulas are rough guides, not personal targets. Use them as a starting reference point, but combine with body fat percentage, waist measurements, and how you feel to get a complete picture of your health status.