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Ideal Body Weight Calculator (IBW and Adjusted Weight)
Ideal body weight (IBW) by the Devine formula is 50 kg for men or 45.5 kg for women, plus 2.3 kg for every inch of height over 5 feet. A man who is 5 ft 10 in has an IBW of 50 + 2.3 × 10 = 73 kg (161 lb). Adjusted body weight is IBW + 0.4 × (actual weight − IBW). This calculator shows both, plus Robinson, Miller and Hamwi for comparison.
Prepared by Prospyr · Reviewed October 3, 2026 · Free, no sign-up, runs in your browser
Ideal body weight (Devine)
160.9 lb
73 kg. At 70 inches tall.
Adjusted body weight
188.6 lb
Actual weight 230 lb, which is 143% of ideal.
Adjusted = IBW + 0.4 × (actual − IBW) = 73 + 0.4 × (104.3 − 73) = 85.5 kg.
| Formula | kg | lb |
|---|---|---|
| Devine (1974) | 73 | 160.9 |
| Robinson (1983) | 71 | 156.5 |
| Miller (1983) | 70.3 | 155 |
| Hamwi (1964) | 75 | 165.3 |
A math aid. Ideal body weight is a height-based reference number, not a health target. Which weight a protocol or label uses is the treating provider's decision.
IBW formulas: Devine, Robinson, Miller and Hamwi
Each formula gives a base weight at 5 feet (60 inches), then adds a fixed amount per extra inch.
| Formula | Men | Women |
|---|---|---|
| Devine (1974) | 50 kg + 2.3 kg/in | 45.5 kg + 2.3 kg/in |
| Robinson (1983) | 52 kg + 1.9 kg/in | 49 kg + 1.7 kg/in |
| Miller (1983) | 56.2 kg + 1.41 kg/in | 53.1 kg + 1.36 kg/in |
| Hamwi (1964) | 48 kg + 2.7 kg/in | 45.5 kg + 2.2 kg/in |
The “/in” amount applies to each inch of height over 60. Devine is the one most people mean by an IBW calculator, and it is the default here. The IBW formulas by height are close to each other because they came from the same kind of data.
Adjusted body weight calculator: formula and worked example
Adjusted body weight (ABW) is IBW plus a fraction of the excess: ABW = IBW + 0.4 × (actual − IBW).
- Man, 5 ft 10 in (70 in), actual weight 230 lb = 104.3 kg.
- Devine IBW = 50 + 2.3 × (70 − 60) = 73 kg.
- Excess over IBW = 104.3 − 73 = 31.3 kg.
- ABW = 73 + 0.4 × 31.3 = 85.5 kg (188.6 lb).
The tool does this when you enter an actual weight. It reports what the formula returns and does not say which weight to use for any purpose.
How to use the IBW calculator, ABW and the comparison table
Choose ft/in/lb or cm/kg, pick the sex the formula uses, and enter height and weight. The result updates as you type and the comparison table lists all four IBW formulas for the same height, in kg and lb, so you can document which one you used.
The formulas were written with binary sex terms. Use whichever the source protocol or form specifies.
For aesthetic and surgical practices
Practices see ideal and adjusted weights on pre-procedure forms, anesthesia records and weight-management intake. Use this to get the number consistently with the formula named. It stops there; what to do with it is the provider's call.
Prospyr's aesthetic EMR keeps height, weight and calculated values with the chart. For other body-size math, see the BSA calculator.
Frequently asked questions
How do you calculate ideal body weight?
With the Devine formula, ideal body weight is 50 kg for a man or 45.5 kg for a woman, plus 2.3 kg for each inch of height above 60 inches. A woman who is 5 ft 5 in comes to 45.5 + 2.3 × 5 = 57 kg (125.7 lb). Enter your height and sex above and the calculator does the same steps.
What is the adjusted body weight formula?
Adjusted body weight = IBW + 0.4 × (actual weight − IBW). Published studies write it this way, with 0.4 as the correction factor. A 5 ft 10 in man at 230 lb (104.3 kg) with an IBW of 73 kg has an adjusted weight of 73 + 0.4 × 31.3 = 85.5 kg, about 188.6 lb.
What is the difference between IBW and ABW?
IBW is a height-based reference weight and ignores how much a person actually weighs. ABW (adjusted body weight) starts at IBW and adds 40 percent of the difference between actual weight and IBW, so it falls between the two. ABW is only defined when actual weight is known and is mostly of interest above IBW.
Which IBW formula should I use: Devine, Robinson, Miller or Hamwi?
Use the one your protocol or reference names. A 2000 review in the Annals of Pharmacotherapy found the equations are similar because they were all built from the same kind of height-weight tables, and concluded any one of them may be used to estimate IBW. The table above shows how far apart they land for your height.
Is ideal body weight the same as a healthy weight?
No. IBW is a number calculated from height and sex. It does not account for muscle, frame size, age or health, and it is not a weight goal. For a body-size screening number, see a BMI tool, and know that BMI has its own limits.
Does the formula work for people shorter than 5 feet?
The published equations are written as an amount added per inch over 60 inches. Below 60 inches they are extended past the range they were built for, so the result is less reliable. The calculator still shows a number and flags it.
Can I use this to dose a drug or set a fluid rate?
No. This page does arithmetic on height, sex and weight only. Which weight a drug label, protocol or order uses, and any dose, are decisions for the treating provider.
Sources and scope
- Pai MP, Paloucek FP. The origin of the "ideal" body weight equations. Ann Pharmacother. 2000;34(9):1066-1069. PMID 10981254
Peer-reviewed history of the Devine and related IBW equations; concludes any one of them may be used to estimate IBW. The per-inch constants for Devine, Robinson, Miller and Hamwi are the ones in common published use.
- Association between obesity and kidney outcomes in critically ill patients with acute kidney injury receiving continuous renal replacement therapy: a secondary analysis of the multicenter CRRTnet study. Crit Care. 2026 (PMC13045041)
Peer-reviewed example of the adjusted body weight formula as used in the literature: Adj-BW = [(actual − IBW) × 0.4] + IBW. Cited only for the formula.
A math aid, not medical advice. Ideal and adjusted weight are formula outputs, not health goals or dosing weights; which weight a protocol or label uses is the treating provider's decision.