Ideal Weight Calculator – Find Your Ideal Body Weight

Ideal weight formulas: Robinson, Devine, Hamwi, Miller

"Ideal" body weight formulas estimate a target weight for a given height and sex. They were developed at different times and for different purposes—drug dosing, nutrition screening, and population studies. Because they use slightly different constants and base heights, results vary by a few kilograms. Understanding where each formula comes from helps you interpret the range you see.

Robinson (1983)

The Robinson formula was derived from regression analyses of height and weight data. For men it uses 52 kg as base weight for 5 feet, plus 1.9 kg per inch over 5 ft; for women, 49 kg plus 1.7 kg per inch. It tends to produce moderate values and is sometimes used in research and clinical settings.

Devine (1974)

The Devine formula was developed for calculating drug dosages, where body size affects pharmacokinetics. Men: 50 kg + 2.3 kg per inch over 5 ft. Women: 45.5 kg + 2.3 kg per inch. It is one of the most cited formulas and often produces values in the middle of the spread. Because it was designed for dosing, it does not necessarily represent "healthiest" weight for everyone.

Hamwi (1964)

The Hamwi method is one of the oldest still in use. Men: 48 kg + 2.7 kg per inch over 5 ft. Women: 45.5 kg + 2.2 kg per inch. It can give slightly lower values than Devine for the same height. It was developed in an era when population body weights differed from today, so some clinicians consider it a conservative estimate.

Miller (1983)

The Miller formula was published the same year as Robinson but with different constants. Men: 56.2 kg + 1.41 kg per inch over 5 ft. Women: 53.1 kg + 1.36 kg per inch. It often yields the highest values of the four, which can be useful as an upper reference. Like the others, it is a population-based estimate, not personalized to body fat or muscle.

Why results vary

The four formulas use different base weights and different slopes (kg per inch above 5 ft). Small differences in those numbers compound with height, so a tall person may see a wider spread (e.g. 5 kg) than a shorter person. None of the formulas account for age, frame size, or body composition. That is why we show the range and the average—to give you a band of reasonable estimates rather than a single "correct" number.

Ideal weight vs. BMI

BMI (body mass index) is weight divided by height squared and is used to categorize underweight, normal, overweight, and obese. Ideal weight formulas effectively reverse-engineer a weight that would land you in the "normal" BMI range (roughly 18.5–24.9) for your height. So if your ideal weight average falls in the middle of the formula range, your BMI at that weight would typically be in the low 20s. BMI does not distinguish muscle from fat, so athletes may weigh more than "ideal" and still be healthy. For a full picture, use both ideal weight and BMI or body fat as references.

Limitations of ideal weight

Ideal weight is a statistical concept, not a medical prescription. It does not account for muscle mass, bone density, age, or ethnicity. Some people are healthiest above or below the formula range. Use this calculator for general guidance and trend tracking. For personalized targets—especially if you have health conditions or specific goals—consult a doctor or dietitian.