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Adjusted Body Weight Calculator
Adjusted body weight (AdjBW) is a clinical estimate used in drug dosing and nutrition planning for people who weigh well above their ideal body weight. This free calculator finds your ideal body weight with the Devine formula, then applies the standard 0.4 correction factor to get your adjusted weight. You will see both values in kilograms and pounds. Results are for education only and are not medical advice.
How to use
- Select your sex.
- Enter your height in feet and inches.
- Enter your actual weight in pounds.
- Click Calculate to see your ideal and adjusted body weight.
Worked example
Take a man who is 5 ft 8 in tall and weighs 220 lb. Step 1: inches over 5 feet = 68 - 60 = 8. Step 2: ideal body weight = 50 + 2.3 x 8 = 68.4 kg (150.8 lb). Step 3: convert actual weight to kg: 220 / 2.20462 = 99.8 kg. Step 4: adjusted body weight = 68.4 + 0.4 x (99.8 - 68.4) = 68.4 + 12.6 = 81.0 kg (178.5 lb).
Notice the adjusted figure sits between ideal (68.4 kg) and actual (99.8 kg). That middle ground is the whole point: it corrects for excess weight without ignoring it.
When adjusted body weight does not apply
If you weigh at or below your ideal body weight, there is no excess to adjust for, and clinicians simply use actual body weight. These formulas are also designed for adults only, not children. And they are dosing and nutrition tools, not verdicts on your health or appearance.
Always confirm medication dosing with a qualified clinician. This page is educational and is not medical advice.
Frequently asked questions
What is adjusted body weight used for?
Clinicians use it to dose certain medications and estimate nutrition needs in patients who weigh well above their ideal body weight. Drug distribution differs in excess tissue, so actual weight can overestimate the right dose.
What is the difference between ideal and adjusted body weight?
Ideal body weight (IBW) is a height-based estimate of a reference weight. Adjusted body weight (AdjBW) starts from IBW and adds back 40 percent of the excess above it. The result lands between ideal and actual weight, giving a more realistic basis for dosing than either extreme.
What is the Devine formula?
It estimates ideal body weight from height: 50 kg plus 2.3 kg per inch over 5 feet for men, and 45.5 kg plus 2.3 kg per inch over 5 feet for women. It was developed for drug dosing, not as a fitness target.
Devine vs Robinson: which formula does this calculator use?
This calculator uses the Devine formula, the most common choice for adjusted body weight work. Robinson's formula gives slightly different numbers (52 kg + 1.9 kg per inch over 5 feet for men, 49 kg + 1.7 kg per inch over 5 feet for women). The difference is small and both are estimates, not exact science.
Why the 0.4 correction factor?
The 0.4 factor is a clinical convention. It adds back 40 percent of the excess weight above ideal, on the theory that excess tissue still needs some drug or nutrient exposure. Other factors exist, but 0.4 is the most common for dosing.
What is nutritional body weight?
Nutritional body weight uses the same idea with a smaller 0.25 factor instead of 0.4, and dietitians prefer it when estimating energy and protein needs. Adjusted body weight with 0.4 remains the usual choice for drug dosing.
What if I weigh less than my ideal body weight?
Then adjusted body weight does not apply. Clinicians typically use actual body weight in that case. The calculator will note this when it happens.
Is ideal body weight a good fitness goal?
Not necessarily. The Devine formula was built for dosing drugs, and it ignores muscle mass and frame size. Use it for its clinical purpose, and judge fitness by strength, measurements, and health markers.