Ideal Weight Calculator
See your ideal body weight calculated four different ways at once. The Devine, Robinson, Miller, and Hamwi formulas were each built decades apart for clinical use, and they don't always agree, so this tool shows all four side by side instead of picking a winner.
Your result will appear here
Enter your height and click calculate to compare ideal weight across four formulas.
Quick Answer
This calculator runs your height and sex through four established formulas (Devine, Robinson, Miller, and Hamwi), each of which adds a fixed weight per inch of height above 5 feet, and shows you all four results plus their average.
How It Works: Formula & Variables
- Devine (1974)
- Men: 50 kg + 2.3 kg per inch over 5 ft. Women: 45.5 kg + 2.3 kg per inch over 5 ft.
- Robinson (1983)
- Men: 52 kg + 1.9 kg per inch over 5 ft. Women: 49 kg + 1.7 kg per inch over 5 ft.
- Miller (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.
- Hamwi (1964)
- Men: 48.0 kg + 2.7 kg per inch over 5 ft. Women: 45.5 kg + 2.2 kg per inch over 5 ft.
Worked Examples
Example: Man, 5'10" (70 inches)
10 inches over 5 feet. Devine: 50 + 2.3×10 = 73 kg (161 lb). Robinson: 52 + 1.9×10 = 71 kg (157 lb). Miller: 56.2 + 1.41×10 = 70.3 kg (155 lb). Hamwi: 48 + 2.7×10 = 75 kg (165 lb). The four formulas span about 155 to 165 lb for the same height.
Example: Woman, 5'5" (65 inches)
5 inches over 5 feet. Devine: 45.5 + 2.3×5 = 57 kg (126 lb). Robinson: 49 + 1.7×5 = 57.5 kg (127 lb). Miller: 53.1 + 1.36×5 = 59.9 kg (132 lb). Hamwi: 45.5 + 2.2×5 = 56.5 kg (125 lb). Here the four formulas land closer together, around 125 to 132 lb.
Key Concepts
Built for medicine, not fitness: The Devine formula was created to help calculate drug dosages, not to define a fitness or aesthetic target. The others share similar clinical origins.
Height-only, no build: None of these formulas ask about frame size, muscle mass, or activity level, which is the main reason they should be read as a rough range rather than a precise number.
Averaging isn't a shortcut to accuracy: The average of the four formulas isn't inherently more correct, it's just a single number that summarizes where they cluster.
Common Mistakes
Treating the result as a strict target: These formulas produce a reference point, not a number to chase. A healthy weight range from a BMI calculator or a body fat percentage estimate usually reflects real health goals more closely.
Ignoring muscle mass: An athletic or muscular person will often come out "above ideal weight" by these formulas despite having a healthy, low body fat percentage.
Picking the number you like best: Since the four formulas can differ by 5-10 lb, it's tempting to anchor on whichever one gives the most flattering number. Look at the range as a whole instead.
Frequently Asked Questions
None of them is more "correct" than the others. Devine, Robinson, Miller, and Hamwi were all built from different populations for different purposes, mainly medication dosing and clinical nutrition, not fitness. They routinely disagree by 5 kg or more at the same height, which is why this calculator shows all four side by side instead of picking one as the answer.
Each one was derived from a different reference dataset decades apart. The Devine formula (1974) was built for drug dosing calculations, Hamwi (1964) was designed for quick use by dietitians, and Robinson (1983) and Miller (1983) were later attempts to update the older formulas with newer population data. None of them were designed with body composition or athletic goals in mind.
No. All four formulas use only height and sex, so a muscular, athletic person will often be told their 'ideal weight' is lower than their actual healthy weight. Use this alongside a body fat percentage estimate for a fuller picture.
The original formulas were kept deliberately simple, since they were designed to be calculated by hand. Frame size and age matter in practice, which is part of why these numbers work better as a rough reference range than a precise target.
A healthy BMI range or a body fat percentage target usually reflects real-world health goals better than any single ideal-weight number, since both account for your actual height-to-weight ratio or body composition rather than a decades-old population average.