Ideal Body Weight Calculator (Robinson Formula)
Calculate your ideal body weight using the Robinson formula (1983). A refined clinical IBW equation that gives slightly higher estimates than Devine for most heights.
Ideal Body Weight Calculator (Devine Formula)
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.
Optional
lbs
Devine Ideal Body Weight
161 lbs
Healthy range: 145–177 lbs
Ideal Weight (Devine)⧉
161 lbs
1974 formula
Healthy Range (±10%)⧉
145–177 lbs
Difference from IBW⧉
+19 lbs
Above IBW
Adjusted Body Weight⧉
169 lbs
IBW + 0.4 × (actual − IBW)
All IBW Formulas
Devine1974
161 lbs
Robinson1983
157 lbs
Miller1983
155 lbs
Hamwi1964
165 lbs
■ Red line = your actual weight
Ideal body weight is a clinical reference, not a personal health target. It does not account for body composition, frame size, or fitness level. Consult a healthcare professional for personalized guidance.
Planning notes, formulas, and examples
About the Ideal Body Weight Calculator (Devine Formula)
The Devine formula (1974) is one of the most widely used ideal body weight (IBW) equations in clinical practice. It was originally proposed as a dosing reference and later became a common shortcut for estimating a height-based reference weight in pharmacy, ventilation, and nutrition workflows.
The formula uses a base weight at 5 feet of height and adds a fixed amount for each additional inch. That makes it easy to apply consistently, but it also means the result is only a reference value rather than a personalized definition of what someone should weigh.
That distinction matters. "Ideal" body weight in this context is a practical calculation anchor, not a personal health target. Muscularity, body frame, ethnicity, older age, edema, pregnancy, and clinical context can all make an individual's healthiest weight differ from the Devine estimate.
When This Page Helps
The Devine formula is useful because many medical and pharmacy references still express dosing or ventilation assumptions relative to ideal body weight. If you want to understand those calculations, knowing the Devine estimate gives you the same reference point those formulas are using.
Outside that context, the number is best treated as orientation rather than a verdict. A healthy adult weight range is broader than any single IBW equation, and actual goals should be individualized.
How to Use the Inputs
- Select your sex (the formula differs for men and women).
- Enter your height in feet/inches or centimeters.
- View your ideal body weight and healthy range (±10%).
- Compare with your actual weight to see the difference.
- Review the comparison with other IBW formulas.
Formula used
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%Example Calculation
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.
Tips & Best Practices
- The Devine formula was designed for adults 5'0" and taller. Results below this height should be interpreted cautiously.
- IBW is a population reference, not a personal goal. Muscular individuals will naturally weigh more than their IBW.
- For drug dosing purposes, adjusted body weight = IBW + 0.4 × (actual weight − IBW) is used for obese patients.
- Frame size (small, medium, large) can shift your ideal range by 5–10%. The Devine formula assumes a medium frame.
- Compare IBW from multiple formulas (Devine, Robinson, Miller, Hamwi) for a more balanced picture.
Comparing the Four Major IBW Formulas
| 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 |
Clinical Applications
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.
Sources & Methodology
Last updated:
Methodology
This page applies the Devine ideal body weight equation using the standard sex-specific base values at 5 feet of height and the usual per-inch adjustment above that point. It also shows a simple ±10% reference band and compares the Devine result with Robinson, Miller, and Hamwi estimates so users can see how much the different height-based formulas diverge.
The result is intended as a clinical reference weight rather than a personal health target. Ideal body weight equations are shortcuts used in some dosing, ventilation, and nutrition workflows, but they do not directly measure body composition, frame size, or physical fitness.
Sources
- Gentamicin therapy (Drug Intelligence & Clinical Pharmacy) — Original Devine publication.
- Medication dosing in obese patients (Clinical Pharmacokinetics) — General clinical context for choosing between actual, ideal, and adjusted body weight.
Frequently Asked Questions
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.
More in this topic
Ideal Body Weight Calculator (Miller Formula)
Calculate your ideal body weight using the Miller formula (1983). Gives the highest IBW estimates among the four major formulas — a more generous reference weight for your height.
Ideal Body Weight Calculator (Hamwi Formula)
Calculate your ideal body weight using the Hamwi formula (1964). The oldest major IBW equation, widely used in clinical dietetics with the highest per-inch weight increment.