Ideal Weight Calculator
Compare the Devine, Robinson and Hamwi ideal body weight formulas for your height.
How it works
Enter your height in centimetres or feet and inches and choose male, female or both. The calculator converts your height to inches over 5 feet, applies each formula, and shows the results in kg and lb.
h = height in cm ÷ 2.54 − 60 (inches over 5 ft)
Devine: male 50 + 2.3h female 45.5 + 2.3h
Robinson: male 52 + 1.9h female 49 + 1.7h
Hamwi: male 48 + 2.7h female 45.5 + 2.2h (kg)Example
Height 170 cm: h = 170 ÷ 2.54 − 60 = 6.93. For a man: Devine 50 + 2.3 × 6.93 = 65.9 kg, Robinson 52 + 1.9 × 6.93 = 65.2 kg, Hamwi 48 + 2.7 × 6.93 = 66.7 kg, average 65.9 kg. For a woman the average is 61.0 kg.
Common mistakes
- Treating one formula as the answer. They disagree by a kilogram or more, which is why a range is shown.
- Using the result as a health verdict. The formulas use height only.
- Expecting reliable results for heights under 5 ft. Below that the formulas extrapolate.
Results are estimates and are not a substitute for medical advice.
About this calculator
These three formulas each give an ideal body weight from height alone, with a different base weight for men and women. Each adds a set number of kilograms for every inch of height over 5 feet. This calculator shows all three side by side, their average, and the range from lowest to highest.
They were written for adults 5 feet (152.4 cm) or taller, and below that they extrapolate. They do not take build, muscle or age into account, so treat them as rough references. A BMI-based weight range is shown for comparison, but it measures something different.
Frequently asked questions
Why do the three formulas give different results?
They were developed separately, with different base weights and different amounts per inch. At 170 cm the male results run from 65.2 kg (Robinson) to 66.7 kg (Hamwi).
Do these formulas decide whether my weight is healthy?
No. They are rough references that use height only, and they do not determine health by themselves.
What happens under 5 feet?
The formulas were designed for heights of 5 ft (152.4 cm) and above. Below that the calculator still shows results while they stay above zero, with a note that they may be unreliable.
How is the BMI comparison different?
It shows the weights that give a BMI of 18.5 to 24.9 at your height. That is a separate measure from these formulas, so the two ranges need not match.