Ideal Body Weight Calculator

Where the ideal-weight formulas come from

The Devine, Robinson, Miller and Hamwi formulas were developed between the 1960s and 1980s, mainly to dose medicines that depend on lean body mass. Each starts from a base weight at 5 feet (152.4 cm) and adds a fixed amount per extra inch. For example Devine gives men 50 kg plus 2.3 kg per inch over 5 feet, and women 45.5 kg plus 2.3 kg per inch.

Because they were fitted to different data, the formulas disagree by a few kilograms. Showing all of them together gives a realistic range instead of a single "perfect" number that does not really exist.

Worked example

A woman 168 cm tall is 168 / 2.54 = 66.1 inches, which is 6.1 inches over 5 feet. Devine gives 45.5 + 2.3 × 6.1 = 59.6 kg. Robinson (49 + 1.7 × 6.1) gives 59.4 kg and Miller (53.1 + 1.36 × 6.1) gives 61.4 kg. A sensible target band is therefore roughly 59.5 to 61.5 kg, which also sits inside the healthy BMI range for her height (52 to 70 kg).

Limits

These equations ignore frame size, muscle mass and age, and they are less reliable for people under 5 feet tall. Use the result as a rough guide alongside BMI and waist measurement rather than as a goal you must hit exactly.