Estimate Devine ideal and adjusted body weight in kg or lb, select a protocol factor, review BMI and excess weight, or reverse-solve actual weight or height.

Educational Devine formula estimate for adults. Select the factor required by an applicable protocol; this result is not a dosing or personal weight-goal recommendation.

Weight basis and factor depend on the drug, guideline and clinical context.

Medical safety note: This calculator is for educational use only and is not for dosing medications or making treatment decisions. Whether to use actual, ideal, or adjusted body weight depends on the specific drug/guideline and clinical factors (for example, kidney/liver function). The Devine IBW and selected adjusted-weight formulas are not universally valid (including for children/adolescents, pregnancy, critical illness, edema/ascites, or amputations) unless a clinician directs you. Below 60 inches, the Devine equation is linearly extrapolated from its five-foot anchor. An actual weight below IBW produces an algebraic negative adjustment, which does not establish an appropriate clinical weight. For general “healthy weight” guidance, refer to public-health resources such as CDC BMI/healthy weight pages and discuss personal goals with a licensed clinician.

Adjusted Body Weight Formula

The following formula is used to calculate your adjusted body weight.

ABW = IBW + k × (AW – IBW)
  • Where ABW is your adjusted body weight
  • IBW is your ideal body weight
  • AW is your actual weight.

In this case, your ideal body weight is determined by your height and sex using formulas like the ones below.

Male: IBW = 50 kg + 2.3 kg × (Height – 60 in)
Female: IBW = 45.5 kg + 2.3 kg × (Height – 60 in)

k is the selected adjustment factor: 0.4, 0.5, or a custom value greater than zero and no more than one. These are protocol choices, not interchangeable universal clinical recommendations. The University of Illinois Chicago formula table documents the Devine constants and a 0.4 adjusted-weight expression; clinical weight selection remains context dependent.

Example: With the male constant, a height of 70 inches gives IBW = 50 + 2.3 × 10 = 73 kg. An actual weight of 100 kg and factor 0.4 give adjusted weight = 73 + 0.4 × 27 = 83.8 kg. Intermediate values are not rounded before calculation; displayed values are rounded.

Inverse modes: Actual weight = IBW + (target adjusted weight − IBW) / k. Height in inches = 60 + (target Devine IBW kg − formula constant) / 2.3. The height mode reverses a target IBW, independently of the adjustment factor. Outputs are substituted back into their source equations. BMI uses actual kilograms divided by height in meters squared and does not measure body composition.

Adjusted Body Weight Definition

Adjusted body weight (ABW) is an estimated weight used in some clinical and nutrition calculations—often in obesity—when using actual body weight may overestimate needs for certain formulas. ABW is calculated from ideal body weight (IBW) and actual body weight; it does not measure body composition and does not diagnose health.

In practice, whether ABW is appropriate depends on the specific calculation and guideline being used.

Some healthcare teams may use ABW as one possible input for selected weight-based calculations, but the “right” weight to use can vary by drug, indication, and patient factors.

ABW can be useful because using actual body weight may not be appropriate for every formula in every context. However, ABW is still only an estimate and should be interpreted cautiously.

For example, two people can have the same actual body weight with very different body composition (fat mass vs. muscle mass). The ABW formula does not distinguish between these differences—it simply adjusts a Devine-based IBW toward actual weight by a fixed factor.

How to calculate adjusted body weight?

How to calculate adjusted body weight

  1. First, measure your height

    This value will be used in determining your ideal body weight.

  2. Next, measure your weight

    Using an accurate scale, measure your actual body weight.

  3. Calculate your ideal body weight

    Calculate your ideal body weight using one of the two formulas above.

  4. Calculate your adjusted body weight

    Using your ideal weight and actual weight, calculate your adjusted body weight.

FAQ

What is adjusted body weight?

Adjusted body weight is a mathematical weight descriptor used in selected clinical or nutrition formulas. It does not prescribe nutritional requirements, a medication dose, or a personal goal weight.

What is an ideal body weight?

Ideal body weight is an estimate used in some medical formulas. It is not a diagnostic target and does not by itself determine health. Healthy weight depends on multiple factors; consider discussing goals with a clinician.

Calculator Change Log:

  • 6/13/25 - Added a quick reference tab, interpretation field, and excess weight field for a more in-depth understanding of adjusted body weight and ideal body weight.