Ideal Weight (Hamwi) Calculator

About this calculator

The Hamwi formula, published by Dr. George Hamwi in 1964 for fast bedside estimation, calculates ideal body weight from height and sex using a base-plus-increment method: for men, 48.0 kg for the first 152 cm (5 feet) of height, plus about 2.7 kg for every inch (2.54 cm) above that; for women, 45.5 kg for the first 152 cm, plus about 2.2 kg per additional inch. A 170 cm man, roughly 7 inches over the base height, comes out to about 48.0 + (7 × 2.7) ≈ 67 kg.

Originally designed to speed up drug-dosage calculations that need an estimate of lean body weight rather than actual weight (which can be skewed by fat mass or fluid retention), the Hamwi formula is still used in clinical nutrition assessments and by dietitians as a fast reference point, usually alongside — not instead of — BMI and other modern indices, since like most simple height-based formulas it does not account for frame size or muscle mass.

This calculator takes your height and sex and returns your Hamwi ideal weight using the standard base-plus-increment method.