Calculate your ideal body weight using the Devine formula — the most commonly used IBW calculation in clinical medicine for drug dosing, nutrition planning, and tidal volume estimation.
The Devine formula (1974) is the most widely used ideal body weight (IBW) equation in clinical medicine. Originally developed by Dr. B.J. Devine for calculating drug dosages, it became the de facto standard for estimating a healthy reference weight based on height.
The formula uses a base weight for 5 feet of height and adds a fixed amount per additional inch. While simple, it's been validated in countless clinical applications including mechanical ventilation tidal volumes, aminoglycoside dosing, and nutritional assessments.
It's important to note that "ideal" weight is a clinical reference point, not a personal goal. Body composition, fitness level, and individual factors matter more than any single number. Whether you are a beginner or experienced professional, this free online tool provides instant, reliable results without manual computation. By automating the calculation, you save time and reduce the risk of costly errors in your planning and decision-making process. This tool handles all the complex arithmetic so you can focus on interpreting results and making informed decisions based on accurate data.
The Devine formula is the clinical standard. Doctors, pharmacists, and dietitians use it daily for drug dosing, ventilator settings, and nutritional planning. Knowing your Devine IBW gives you a medically relevant reference point, though actual healthy weight ranges are broader than any single number suggests. Having a precise figure at your fingertips empowers better planning and more confident decisions.
Men: IBW = 50.0 + 2.3 × (height in inches − 60) Women: IBW = 45.5 + 2.3 × (height in inches − 60) Result in kg. For heights below 5'0", the base value is adjusted downward. Healthy range: IBW ± 10%
Result: IBW: 73.0 kg (161 lbs) | Healthy range: 65.7–80.3 kg (145–177 lbs)
For a male at 5'10" (70 inches): IBW = 50.0 + 2.3 × (70 − 60) = 50.0 + 23.0 = 73.0 kg (161 lbs). The healthy range (±10%) is 65.7–80.3 kg (145–177 lbs). This is a clinical reference, not a personal target.
| Formula | Men (5'10") | Women (5'5") | Year | |---|---|---|---| | Devine | 73.0 kg | 57.0 kg | 1974 | | Robinson | 71.0 kg | 57.5 kg | 1983 | | Miller | 72.3 kg | 60.5 kg | 1983 | | Hamwi | 75.0 kg | 57.3 kg | 1964 |
The Devine IBW is deeply embedded in clinical practice: ventilator tidal volumes (6–8 mL per kg IBW), gentamicin dosing, phenytoin loading doses, and caloric need calculations. Anesthesiologists, ICU physicians, and pharmacists rely on it daily. While newer body composition measurements are more accurate for individual assessment, IBW remains indispensable for quick clinical calculations.
The Devine formula gained widespread adoption because it was published in a widely-read drug dosing reference (Gentamicin therapy, 1974) and subsequently embedded in medical textbooks, ventilator protocols, and pharmacy guidelines. Its simplicity (linear equation, easy mental math) made it practical for bedside use. While not necessarily more accurate than alternatives, its ubiquity in clinical practice has made it the default standard.
The formula has known limitations. It was derived empirically rather than from large population studies, tends to underestimate ideal weight for shorter people and overestimate for very tall people, and doesn't account for frame size, ethnicity, or age. For clinical purposes (drug dosing, ventilation), it's been validated through decades of use. For personal weight goals, it's best used as one data point among several.
The Devine formula was designed for heights ≥ 60 inches (5'0"). Below this height, the formula technically yields negative corrections (subtracting from the base weight). Some clinicians use the base value (50 kg for men, 45.5 kg for women) as a minimum, while others switch to BMI-based estimates for shorter stature. The formula is least reliable at very short or very tall heights.
Devine gives the lowest values among the four major formulas, especially for taller individuals. Robinson (1983) gives slightly higher results, Miller gives the highest values, and Hamwi falls in between. The differences can be 3–8 kg depending on height. Using the average of all four formulas may provide a more balanced estimate.
IBW is a clinical reference point, not necessarily a personal target. A healthy weight range is broader — BMI 18.5–24.9 defines "normal weight" for a wide span. A fit, muscular person might weigh 15–20% above their Devine IBW and be perfectly healthy. Use IBW as general orientation, but consider body composition, fitness level, and overall health markers for personal goals.
Adjusted Body Weight (ABW) accounts for the fact that excess fat tissue also contains some lean tissue. ABW = IBW + 0.4 × (actual weight − IBW). It's used for drug dosing in obese patients, where using actual weight would overdose and using IBW would underdose. The 0.4 factor represents the approximate proportion of lean tissue in excess weight.