Ideal body weight (IBW) was initially introduced by Devine in 1974 to allow estimation of drug clearances in obese patients; researchers have since shown that the metabolism of certain drugs relates more to IBW than total body weight. The term was based on the use of insurance data that demonstrated the relative mortality for males and females according to different height–weight combinations.

The most common estimation of IBW is by the Devine formula; other models exist and have been noted to give similar results. Other methods used in estimating the ideal body weight are body mass index and the Hamwi method.

Devine formula

The Devine formula for calculating ideal body weight in adults is as follows:

Male ideal body weight = 50 kilograms (110 lb) + 2.3 kilograms (5.1 lb) * (height (in) − 60)

Female ideal body weight = 45.5 kilograms (100 lb) + 2.3 kilograms (5.1 lb) *(height (in) − 60)

Hamwi method

The Hamwi method is used to calculate the ideal body weight of the general adult:

Male ideal body weight = 106 pounds (48 kg) + 6 pounds (2.7 kg) * (height (in) − 60)

Female ideal body weight = 100 pounds (45 kg) + 5 pounds (2.3 kg) * (height (in) − 60)