What Is Ideal Body Weight?
Ideal body weight (IBW) is an estimated weight range associated with the lowest health risks for a given height and gender. Clinicians use IBW to dose medications, set ventilator tidal volumes, and counsel patients on weight management. Five formulas dominate the literature: Devine (1974), Robinson (1983), Miller (1983), Hamwi (1964), and Broca (19th century).
How Each Formula Works
All height-based formulas share a similar structure: a base weight for someone 5 feet tall plus an increment per additional inch. Devine adds 2.3 kg per inch for males and the same for females from a lower base. Robinson uses 1.9 and 1.7 kg increments respectively. Miller uses 1.41 and 1.36 kg. Hamwi uses 2.7 and 2.2 kg. Broca simply subtracts a constant from height in centimeters.
Interpreting the Average Range
Because each formula produces a slightly different estimate, the calculator displays the minimum and maximum across all five as an average ideal range. This range gives you a realistic band rather than a single number, acknowledging the inherent uncertainty in any weight estimation based solely on height and gender.
Limitations and When to Seek Professional Advice
Ideal weight formulas do not account for age, ethnicity, frame size, muscle mass, or body fat distribution. They are screening tools, not diagnoses. If your actual weight falls outside the estimated range, consult a healthcare provider who can evaluate your full health profile including blood pressure, cholesterol, blood glucose, and body composition analysis.
