Ideal Weight Calculator
A Clinical Shortcut From Before Modern Body Composition Testing
Long before bioelectrical scales or DEXA scans, hospital pharmacists needed a fast way to estimate a patient's weight for drug dosing calculations — particularly for medications dosed by body weight. Dr. B.J. Devine published his formula in 1974 to solve exactly that problem, and despite newer methods existing today, it's still the reference formula used in clinical dosing calculations because of its simplicity and reliability across a wide population.
The Formula
Women: IBW (kg) = 45.5 + 2.3 × (Height in inches − 60)
The formula is anchored at 5 feet (60 inches) and adds 2.3 kg for every inch above that height. Metric height inputs are converted to inches internally before the calculation runs.
Where This Is Actually Used
- Medication dosing — many drugs, especially in anesthesia and critical care, are dosed using ideal or adjusted body weight rather than actual weight to avoid over- or under-dosing.
- Fitness goal-setting — a reasonable starting reference range, though it should be balanced with body composition and personal frame size.
- Nutrition planning — dietitians sometimes use IBW alongside actual weight to set calorie and protein targets for patients well outside a typical weight range.
Devine Formula at Sample Heights
| Height | Men (IBW) | Women (IBW) |
|---|---|---|
| 5'0" (152 cm) | 50.0 kg | 45.5 kg |
| 5'6" (168 cm) | 63.8 kg | 59.3 kg |
| 5'10" (178 cm) | 73.2 kg | 68.7 kg |
| 6'0" (183 cm) | 77.8 kg | 73.3 kg |
Figures calculated directly from the Devine formula at whole-inch heights; individual results depend on exact height entered.
How to Use This Calculator
- Choose Metric (cm) or Imperial (in) units.
- Select Male or Female.
- Enter your height.
- Select Calculate to see your ideal body weight in both kg and lb.
Related Calculations
Compare this reference figure against your actual BMI using the BMI Calculator, or estimate your lean tissue directly with the Lean Body Mass Calculator.