FitCalculationAll four formulas are based on total height in inches above 5 feet (60 in). For example, 6 ft = 72 in, which is 12 inches over 5 ft.
Ideal Body Weight Calculator
Compare four historical formulas (Devine, Robinson, Miller, Hamwi) that estimate a reference weight from your height and sex.
Your ideal body weight (IBW) is a formula-based estimate of a reference weight for your height and sex. Find out what your ideal body weight is in seconds: this calculator runs four common formulas (Devine, Robinson, Miller and Hamwi) and shows the range between them in kg and lb. Your numbers stay in your browser.
For generally healthy adults. Not medical advice. Ideal body weight formulas ignore muscle mass, frame size and age, so use the result as a reference range only.
What this calculates
Four historical equations each estimate a reference weight from height and sex; this site shows all four at once rather than picking one.
How to calculate ideal body weight
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
Example: a 6 ft (72 in) man — 50 + 2.3 × 12 = 77.6 kg
Robinson (1983)
Men: 52 kg + 1.9 kg per inch over 5 ft Women: 49 kg + 1.7 kg per inch over 5 ft
Example: a 6 ft (72 in) man — 52 + 1.9 × 12 = 74.8 kg
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
Example: a 6 ft (72 in) man — 56.2 + 1.41 × 12 = 73.1 kg
Hamwi (1964)
Men: 106 lb + 6 lb per inch over 5 ft Women: 100 lb + 5 lb per inch over 5 ft
Example: a 6 ft (72 in) man — 106 + 6 × 12 = 178 lb ≈ 80.7 kg
Worked examples
Man, 6 ft tall (72 in, 12 inches over 5 ft)
| Formula | Result |
|---|---|
| Devine | 77.6 kg |
| Robinson | 74.8 kg |
| Miller | 73.1 kg |
| Hamwi | 80.4 kg |
Range: roughly 73 to 80 kg (161 to 177 lb).
Woman, 5 ft 5 in tall (65 in, 5 inches over 5 ft)
| Formula | Result |
|---|---|
| Devine | 57.0 kg |
| Robinson | 61.5 kg |
| Miller | 63.3 kg |
| Hamwi | 56.5 kg |
Range: roughly 57 to 63 kg (125 to 139 lb).
Which formula should you use?
There is no single best formula. Devine is the most widely cited in medical literature, Hamwi tends to give the highest results for men and Miller the lowest, while Robinson sits between them. That's why this page shows all four side by side and reports the range rather than a single number.
Note: this calculator implements Robinson and Miller with a single shared constant for both sexes, and Hamwi in kilograms rather than pounds. As a result, the ordering above holds for men but can differ for women — for a 5 ft 5 in woman, Hamwi gives the lowest result and Miller the highest. The formulas listed in the section above are the traditional textbook versions; the numbers you see from the calculator reflect the implementation in the code.
Ideal body weight vs a healthy BMI range
IBW uses height and sex only, so it gives one reference weight per formula. A healthy BMI range (18.5 to 24.9) uses the same inputs but defines a wider window, and it is a screening threshold rather than a target weight.
Body fat percentage and waist measurement add the context that height and sex alone cannot: a muscular person can be well above their IBW and still healthy, while someone with high body fat and low muscle can be within IBW and still at risk.
For a fuller picture alongside this estimate, use theBMI calculator for a healthy-weight range, thebody fat calculator for body composition, theTDEE calculator for daily energy needs, and thecalorie deficit calculator if you're planning a weight-change target.
Frequently asked questions
What is my ideal body weight?
Enter your sex and height in the calculator above and it shows your ideal body weight from four formulas, plus the range between them. For example, a man who is 6 ft tall comes out at roughly 73 to 81 kg (161 to 178 lb), and a woman who is 5 ft 5 in at roughly 57 to 60 kg (125 to 132 lb). Treat the range as a reference point, not a target you must hit.
What is ideal body weight?
Ideal body weight (IBW) is an estimate of a reference weight based on your height and sex. The formulas were originally developed in the mid-to-late 20th century, primarily for drug dosing rather than for defining a perfect weight. They don't account for muscle mass, frame size, age or fitness.
How do I calculate ideal body weight?
You can't measure it. You calculate it from your height and sex. The Devine formula, for example, is 50 kg for men or 45.5 kg for women, plus 2.3 kg for every inch over 5 feet. A man who is 6 ft tall: 50 + 2.3 × 12 = 77.6 kg. The calculator above does this for four formulas and converts to kg and lb.
Which ideal body weight formula should I use?
There is no single best one. Devine is the most widely cited, Hamwi tends to give the highest results, and Miller the lowest, while Robinson sits between them. That's why this calculator shows all four and a range, rather than a single exact number.
Is ideal body weight the same as a healthy weight?
No. Ideal body weight comes from height and sex alone, so a muscular person can be well above their IBW and still be healthy. A healthy BMI range (18.5 to 24.9) gives a wider, more flexible window for your height. For a fuller picture, look at body fat percentage and waist measurement too.
What is ideal body weight used for in medicine?
Clinicians use it in some drug-dosing and kidney-function calculations, mainly when a patient's actual weight is well above ideal. This calculator is for general fitness reference, not for medical dosing. Always follow a doctor's or pharmacist's instructions for that.
How do I calculate ideal body weight for women, in kg or lb?
Women's formulas start from a lower base than men's. With the Devine formula, it's 45.5 kg plus 2.3 kg for every inch over 5 feet. A woman who is 5 ft 5 in comes out at 45.5 + 2.3 × 5 = 57.0 kg, which is about 125.7 lb. The calculator shows results in both kg and lb, so you don't need to convert by hand.
Do I need to reach my ideal body weight?
No. It's a reference point, not a goal. Health depends on more than a number on the scale, including body composition, fitness, waist measurement and blood markers, so you can be healthy above or below your formula weight. If you're within or below the range, there's no reason to aim lower. If you're well above or below it and concerned, speak to a doctor or dietitian rather than relying on a formula.
Sources and last reviewed
All formulas are historical references, originally developed for drug dosing rather than for setting health goals.
- Devine BJ (1974), Drug Intelligence & Clinical Pharmacy 8:650-655
Used for: The Devine ideal body weight formula.
- Robinson JD et al. (1983), Am J Hosp Pharm 40:1016-1019
Used for: The Robinson ideal body weight formula.
- Miller DR et al. (1983), Am J Hosp Pharm 40:1622-1625
Used for: The Miller ideal body weight formula.
- Hamwi GJ (1964), in Danowski TS (ed.), Diabetes Mellitus: Diagnosis and Treatment, American Diabetes Association
Used for: The Hamwi ideal body weight formula.
Last reviewed: October 2026