Quick answer: For a man 170 cm tall (6.93 inches over 5 ft), the Devine formula gives 50 + 2.3 × 6.93 = 65.9 kg; the healthy BMI range at that height is 53.5 to 72.0 kg.
How it's calculated
Each formula starts from a base weight at 5 ft (152.4 cm) and adds a set amount for every inch above it. Devine: men 50 kg + 2.3 kg/in, women 45.5 + 2.3. Robinson: men 52 + 1.9, women 49 + 1.7. Miller: men 56.2 + 1.41, women 53.1 + 1.36. Hamwi: men 48 + 2.7, women 45.5 + 2.2.
Devine's formula was published to work out drug doses and is still the one most used in hospitals, so it is shown as the main result. Robinson and Miller refitted it to later life-insurance height–weight data.
None of these formulas know your frame size, muscle or age, and they were not built from health outcomes. They give one number where a range of weights is healthy. The healthy BMI range shown alongside is a better guide for most adults; see the healthy weight calculator for it in full.
Worked examples
- Man, 170 cm: Devine 65.9 · Robinson 65.2 · Miller 66.0 · Hamwi 66.7 kg
- Woman, 160 cm (2.99 in over 5 ft): Devine 52.4 · Robinson 54.1 · Miller 57.2 · Hamwi 52.1 kg
- Man, 5 ft 10 in: Devine 50 + 2.3 × 10 = 73 kg (160.9 lb)
Frequently asked questions
Which ideal weight formula is best?
No single formula is right for everyone. Devine is the most used in clinical practice; the four usually land within a few kilos of each other.
Is ideal weight the same as healthy weight?
Not quite. Ideal weight formulas give a single number; healthy weight is a range (BMI 18.5 to 24.9) that is wider and based on health data.
Do the formulas work for short people?
They were built for heights from 5 ft up. Below that the result is a rough extension.
Where do these formulas come from?
Several were first made for medical use. The Devine formula, for example, was published in 1974 to help calculate medicine doses, not to set a goal weight.
Should I aim for the exact number?
No. Treat it as a rough guide. Build and muscle vary, so the healthy BMI range shown beside it is a more realistic target.
Why are the results different for men and women?
Each formula has its own base weight and amount per inch for each sex, because men on average carry more muscle and bone at the same height.