How to use this calculator
On the Ideal Weight tab, choose your units, enter your height and select your sex. The calculator returns your ideal body weight from five classic clinical formulas at once, along with a consensus range, a midpoint, and the healthy BMI range for your height so you can compare. On the Ponderal Index tab, enter your height and current weight to get your Ponderal Index — a height-adjusted alternative to BMI.
What is ideal body weight?
Ideal body weight (IBW) is an estimate of a healthy weight for a person of a given height and sex. The concept comes from medicine, where it has been used for decades to calculate medication dosages, set ventilator settings and guide clinical nutrition. It is a single reference figure, not a strict target — real healthy weights span a range around it.
Because several researchers have published their own versions over the years, there is no one "official" ideal weight number. The formulas agree closely but not exactly. That is why this calculator shows all five and a consensus range rather than pretending there is a single correct answer.
The five ideal weight formulas
Each formula starts from a base weight at 5 feet (60 inches) of height and adds a fixed amount for every inch above that. They differ in the base weight and the per-inch increment.
Men: 50.0 kg + 2.3 kg × (inches over 60)
Women: 45.5 kg + 2.3 kg × (inches over 60)
// Hamwi (1964)
Men: 48.0 kg + 2.7 kg × (inches over 60)
Women: 45.5 kg + 2.2 kg × (inches over 60)
// Robinson (1983)
Men: 52.0 kg + 1.9 kg × (inches over 60)
Women: 49.0 kg + 1.7 kg × (inches over 60)
// Miller (1983)
Men: 56.2 kg + 1.41 kg × (inches over 60)
Women: 53.1 kg + 1.36 kg × (inches over 60)
// Broca index (European) — uses height in cm
Men: (height cm − 100) × 0.90
Women: (height cm − 100) × 0.85
Sources: Devine, B. J. (1974). Gentamicin therapy. Drug Intelligence & Clinical Pharmacy, 8, 650–655. Robinson, J. D. et al. (1983) and Miller, D. R. et al. (1983), American Journal of Hospital Pharmacy. Hamwi, G. J. (1964), in Diabetes Mellitus: Diagnosis and Treatment. Broca, P. (19th century), modified Broca index.
How the formulas compare
For a typical adult the five methods land within a few pounds of each other. The Hamwi formula tends to give the highest figure, Miller and Broca the lowest, and Devine sits in the middle — which is part of why Devine remains the clinical default. Worked example for a 5 foot 10 inch man:
| Formula | Ideal weight | Notes |
|---|---|---|
| Hamwi | 165 lbs (75 kg) | Highest estimate |
| Devine | 161 lbs (73 kg) | Clinical standard |
| Robinson | 157 lbs (71 kg) | Lower than Devine |
| Miller | 155 lbs (70 kg) | Lowest of the US formulas |
| Broca | 155 lbs (70 kg) | European method |
The spread of roughly 10 lbs between the highest and lowest formula is normal. Treat the range, not any single number, as your reference.
Ideal weight vs the healthy BMI range
It is worth comparing your ideal weight figure to your healthy BMI range, which the calculator shows alongside it. The ideal weight formulas target a single point that usually corresponds to a BMI of about 21 to 23 — comfortably inside the healthy band. The healthy BMI range of 18.5 to 24.9 is wider, so a weight a little above your "ideal" figure can still be entirely healthy.
If you want to work backwards from a specific goal BMI to an exact target weight, use the reverse BMI calculator. To see every height's healthy band at a glance, see the BMI chart.
What is the Ponderal Index?
The Ponderal Index (PI), also called the Corpulence Index, is a body-shape measure like BMI but it divides weight by height cubed instead of squared. That extra power of height makes it scale more accurately for people who are very tall or very short, where BMI tends to over- or under-state body mass.
PI = Weight (kg) ÷ Height (m)³
// Example: 70 kg at 1.78 m
70 ÷ 1.78³ = 12.4 kg/m³
For most adults the Ponderal Index falls between roughly 11 and 15 kg/m³, with the mid-range considered typical. Because it is less standardized than BMI it has no universally agreed category cutoffs, so treat it as a complementary signal rather than a diagnosis — particularly useful if you are notably tall or short and BMI feels off.
Important
Not medical advice. Ideal body weight formulas are population estimates that ignore frame size, muscle mass, body fat and age. A muscular athlete will weigh well above their "ideal" figure while being perfectly healthy. Use these numbers as a rough reference, not a goal to force your body toward.
- These formulas are for adults. They are not valid for children or teenagers.
- Very tall, very short, highly muscular or pregnant individuals should not rely on these formulas — speak with a clinician.
- If you have or suspect an eating disorder, please seek professional support before setting any weight target.
Why is there no single ideal weight?
Each formula was developed for a different purpose and population. Devine built his for drug dosing in 1974. Hamwi created a quick bedside rule for diabetes care in 1964. Robinson and Miller refined the numbers in 1983 against different reference data. None of them measured body composition — they all map height and sex to a weight. That is both their strength (anyone can compute them instantly) and their weakness (they cannot tell muscle from fat). The honest answer is that "ideal weight" is a useful estimate with a built-in margin of error of several pounds.
Frequently asked questions
Ideal body weight is an estimate of a healthy weight for your height and sex, based on classic clinical formulas. Because the formulas disagree slightly, it is best read as a range rather than a single number. For a 5 foot 10 inch man the formulas cluster around 155 to 165 lbs (70 to 75 kg); for a 5 foot 4 inch woman, around 118 to 129 lbs (54 to 58 kg).
The Devine formula, published in 1974, estimates ideal body weight as 50 kg plus 2.3 kg for each inch over 5 feet for men, and 45.5 kg plus 2.3 kg per inch over 5 feet for women. It was originally designed for medication dosing and is the most widely used ideal weight formula in medicine.
The Broca index is a European method that estimates ideal weight from height in centimeters. The modified version takes height in cm minus 100, then subtracts 10 percent for men or 15 percent for women. So a 178 cm man has a Broca ideal weight of about 70 kg.
No single formula is definitively most accurate, because none of them account for body composition, frame size or muscle mass. The Devine formula is the clinical standard, the Robinson and Miller formulas tend to give slightly lower values, and Hamwi gives slightly higher. Using the range across all formulas, alongside the healthy BMI range, gives the most balanced picture.
Not exactly. Ideal body weight formulas target a single point that usually falls near the middle of the healthy BMI range. The healthy BMI range (18.5 to 24.9) is wider and gives a band of acceptable weights. A weight slightly above your ideal body weight figure can still be perfectly healthy by BMI.
The Ponderal Index, also called the Corpulence Index, is your weight in kilograms divided by your height in meters cubed. Unlike ideal weight formulas it uses your actual weight. It scales better than BMI for very tall or very short people. A typical adult value falls between roughly 11 and 15 kg/m³.
The formulas are most reliable for heights between about 5 feet and 6 feet 4 inches. Below 5 feet they can underestimate a healthy weight, and at extreme heights they drift from real-world healthy weights. For people outside the typical range, the Ponderal Index and a clinician's judgment are more reliable.
The classic formulas use only height and sex, not age. In practice a healthy weight can drift slightly higher with age, and research suggests older adults may have the lowest mortality risk at a modestly higher weight. Treat the formula output as a young-to-middle-adult reference point.