Use this free Adjusted Body Weight calculator to estimate ABW from your Ideal Body Weight (IBW) and your current weight. It’s commonly used in clinical dosing and nutrition math when actual weight is significantly above IBW. Choose Devine or Hamwi, enter height + weight, and get ABW instantly—no signup.
Pick your unit system, then enter height and current weight. This calculator will compute Ideal Body Weight (IBW) using your chosen method, then compute Adjusted Body Weight (ABW) using the selected adjustment factor. You’ll also see how far above IBW you are (percent).
Adjusted Body Weight (often abbreviated ABW or AdjBW) is a practical “middle” weight used in some clinical and sports-nutrition calculations. The idea is simple: when someone’s current (actual) weight is significantly above their Ideal Body Weight (IBW), using actual weight in an equation can sometimes overestimate needs (for example, in certain medication dosing or nutrition equations), because not all “extra” body mass behaves like lean tissue.
ABW aims to correct that by counting some of the difference between actual weight and IBW — not all of it. That “some” is controlled by an adjustment factor (commonly 0.40, sometimes 0.25–0.50 depending on a protocol). This calculator lets you pick the factor, because different use cases and institutions use different standards.
ABW depends on IBW, so we compute IBW first using one of two popular height-based formulas: Devine (most common in many clinical references) or Hamwi (another widely used classic). Both use height above 5 feet (60 inches) and produce a reasonable “reference weight” for adults. These formulas are not designed for children and do not account for body composition, age, or ethnicity — they are simple height-based estimates.
Important: If your height is below 5 feet, these equations still work mechanically by subtracting inches, but the estimate becomes less reliable. That’s why this page is best treated as a calculator for learning and reference, not a substitute for medical guidance.
A common rule-of-thumb is to use ABW only when actual weight is at least 120% of IBW. That’s why this calculator includes a drop-down for the “use ABW when weight ≥ ___ of IBW” threshold. If your current weight is below that threshold, we’ll still show ABW, but we’ll label whether the “ABW assumption” is typically needed.
Once you have IBW, ABW is a one-line equation:
ABW = IBW + factor × (Actual Weight − IBW)
The most common factor is 0.40, which assumes about 40% of the weight above IBW behaves like “usable” mass for the equation you’re feeding ABW into. A smaller factor like 0.25 is more conservative (counts less of the extra weight), and a larger factor like 0.50 counts more of it.
Example: A male who is 5'10" (70 inches) and weighs 240 lb. Using Devine:
Notice how ABW (≈ 192.5 lb) sits between IBW (≈ 160.9 lb) and actual weight (240 lb). That is exactly the purpose of the adjustment.
Example: A female who is 165 cm and weighs 92 kg. First convert height to inches: 165 cm ≈ 64.96 inches (about 65 inches).
If a protocol asked for a weight input that “partially” accounts for excess body mass, ABW ≈ 71 kg could be the correct input. But always follow the protocol — some situations use actual weight or IBW instead.
Many human energy needs and drug distribution assumptions relate to lean tissue and body water more than to fat mass. When body fat increases, total mass goes up, but not all equations should scale linearly with that mass increase. ABW is a compromise: it counts only a portion of the mass above IBW as “effective” for the target equation. That’s also why ABW is often paired with dosing guidance, renal equations, or nutrition planning — contexts where “which weight to use” matters a lot.
That said, ABW is still a simplification. Two people can have the same height and weight but very different body composition, and ABW will output the same number for both. If you need precision, methods like body composition assessment, clinical judgment, or protocol-specific dosing guidance are more reliable.
This calculator is for educational use and general reference. It does not provide medical advice. Always consult a qualified clinician for medication dosing, nutrition prescriptions, or health decisions.
Actual weight is what the scale shows today. IBW (ideal body weight) is a height-based reference estimate from formulas like Devine or Hamwi. ABW (adjusted body weight) sits between them: it starts with IBW and adds a fraction of the difference between actual weight and IBW.
0.40 is a traditional “default” factor used in many clinical settings when an adjusted weight is needed. It assumes about 40% of the excess weight above IBW contributes to the parameter the equation is trying to model. Some protocols use 0.25 or 0.50; always follow the guidance for your situation.
ABW is typically used only when a specific equation or protocol explicitly calls for it — often when someone’s actual weight is well above IBW (commonly ≥ 120% of IBW). This calculator shows that percentage so you can see whether you’re in that range.
No. ABW is not a goal weight. It’s an input for certain calculations. Healthy weight targets depend on health status, body composition, and professional guidance.
Height-based IBW formulas can underestimate “ideal” weight for muscular individuals and may not reflect healthy athletic bodies. If you have high lean mass, consider using body composition tools (body fat %, lean mass) alongside any weight-based estimates.
Not well. Devine/Hamwi style IBW formulas are commonly framed for adults. For pediatrics, weight assessment typically uses growth charts and age-specific references.
If your current weight is below the selected threshold (for example, below 120% of IBW), many protocols would simply use actual weight or IBW rather than ABW. We still show ABW for learning, but we label whether the “adjusted” assumption is commonly used.
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MaximCalculator provides educational tools and general estimates. Always double-check important health numbers and follow professional guidance.