How it is calculated

Each formula starts from a base weight for 5 ft (152.4 cm) and adds a set amount for every inch above that. The Devine formula, for example, is 50 kg (men) or 45.5 kg (women) + 2.3 kg per inch over 5 ft. The headline figure is the average of the four formulas. The healthy range is the weight that gives a BMI of 18.5–24.9.