If you have ever wondered why a dietitian asks for your height before your weight, this is why. When someone’s actual weight is well above their ideal weight, clinicians often calculate with an adjusted body weight instead — a corrected figure that sits between the two. Enter your sex, height and actual weight below to get your ideal body weight (IBW) and adjusted body weight (AdjBW) instantly.
Uses the Devine ideal body weight formula and a 0.4 correction factor. If your actual weight is below your ideal weight, the adjusted weight shown is simply your actual weight.
What Is Adjusted Body Weight?
Adjusted body weight is a corrected weight used in nutrition and medical care when a person's actual weight is substantially higher than their ideal body weight. It exists because of a simple physiological fact: fat tissue is much less metabolically active than lean tissue such as muscle and organs. A kilogram of fat simply does not burn — or need feeding — like a kilogram of muscle does.
That creates a practical problem. Calculate calorie or protein needs from the full actual weight and you overestimate, sometimes by a lot, because you are budgeting fuel for fat tissue as if it were lean. Calculate from ideal body weight alone and you underestimate instead, because a larger body also carries extra muscle, bone, blood volume and organ mass to support the weight — and that tissue genuinely needs energy and protein.
Adjusted body weight splits the difference. It starts from ideal weight and adds back a fraction — most commonly 40% — of the gap between ideal and actual. The result is the working weight dietitians use for energy and protein estimates in people with obesity, and the same idea appears in some fluid and medication calculations.
You will also meet adjusted weight outside dietetics: pharmacists sometimes dose certain medicines by it, and renal and critical-care teams use it when setting nutrition support for much heavier patients. Wherever it appears, the logic is identical — credit the body for the lean tissue it actually carries, not for every kilogram on the scale.
The Formula
The calculation has two steps. First, ideal body weight from the Devine formula, the standard clinicians have used since the 1970s:
- Men: 50 kg for the first 5 feet of height, plus 2.3 kg for every inch above 5 feet.
- Women: 45.5 kg for the first 5 feet, plus 2.3 kg for every inch above 5 feet.
- Under 5 feet: subtract the same 2.3 kg for each inch below 5 feet.
Then the adjusted weight itself:
AdjBW = IBW + 0.4 × (actual weight − IBW)
The 0.4 is called the correction factor, and it is not universal: some clinicians and hospitals use 0.25 instead, particularly in certain medication-dosing contexts, while 0.4 is the most common choice in nutrition care. This calculator uses 0.4 throughout. One more rule: an adjustment only applies when actual weight is above ideal. If your actual weight is at or below your IBW, there is nothing to adjust — the calculator simply returns your actual weight as the adjusted figure.
Worked Examples
Here is the arithmetic for two examples — you can reproduce both of them in the calculator above.
Example 1 — a man, 5 ft 10 in, actual weight 100 kg.
IBW: 50 + (10 × 2.3) = 73.0 kg. He stands 10 inches over 5 feet, so 10 × 2.3 = 23 kg is added to the 50 kg base.
AdjBW: 73.0 + 0.4 × (100 − 73.0) = 73.0 + 10.8 = 83.8 kg.
Example 2 — a woman, 5 ft 4 in, actual weight 80 kg.
IBW: 45.5 + (4 × 2.3) = 54.7 kg.
AdjBW: 54.7 + 0.4 × (80 − 54.7) = 54.7 + 10.1 = 64.8 kg.
| Weight (Example 1) | kg | lb |
|---|---|---|
| Actual weight | 100.0 | 220 |
| Ideal body weight (IBW) | 73.0 | 161 |
| Adjusted body weight (AdjBW) | 83.8 | 185 |
Read the table as a range of assumptions: 100 kg assumes every kilo is equally hungry, 73.0 kg assumes only the ideal frame needs feeding, and 83.8 kg — the adjusted figure — credits the extra tissue that really is doing work.
Which Weight Should You Use for Calories?
For everyday life, almost certainly your actual weight. If you are a generally healthy adult estimating your daily calories or protein target, use the number on your scale in tools like our maintenance calories calculator and protein calculator. Those tools are built for actual body weight, and for most people they give sensible answers.
Adjusted body weight belongs mainly to clinical settings: hospital dietitians planning nutrition support, tube-feeding calculations, some medication dosing, and dietitian-led weight management where a professional chooses the right basis for the math. Think of this page as educational — it shows you the figure and exactly how it is derived, so the number on a care plan or in a textbook makes sense when you meet it.
And one firm rule: if you are under medical care, the weight basis your care team uses is the right one for you, whatever any calculator says. Ask them the question rather than swapping numbers on your own.
Frequently Asked Questions
What is adjusted body weight?
A corrected body weight used by clinicians when actual weight is well above ideal. It takes ideal body weight and adds a fraction — usually 40% — of the difference between actual and ideal, so calorie and protein estimates are not inflated by fat tissue, which is far less metabolically active than lean tissue.
What is the adjusted body weight formula?
AdjBW = IBW + 0.4 × (actual weight − IBW). The IBW comes from the Devine formula: 50 kg for men or 45.5 kg for women at 5 feet tall, plus 2.3 kg for each inch above 5 feet — and minus 2.3 kg for each inch below.
When is adjusted body weight used instead of actual weight?
Mainly in clinical nutrition: estimating energy and protein needs for patients with obesity, planning tube feeds, and some medication dosing — wherever using the full actual weight would overshoot because of the extra fat mass. For everyday calorie counting at home, actual weight is the standard input.
Is the correction factor 0.25 or 0.4?
Both appear in practice. The 0.4 factor is the most common in nutrition care; 0.25 shows up in some hospital protocols and dosing contexts. This calculator uses 0.4 — and your care team's protocol always outranks a general-purpose tool.