Adjusted Body Weight
Compare actual, ideal and adjusted weight.
Adjusted weight estimate
Weight comparison
Adjusted weight includes 40% of the difference above IBW.
Calculation & assumptions
AjBW = IBW + CF × (Actual weight − IBW)
66.7 + 0.40 × (90.0 − 66.7) = 76.0 kg
Hamwi and Devine can produce different estimates.
View the selected IBW equation
Hamwi (male): 48.0 + 2.7 × (height in inches − 60), in kg.
Hamwi uses rounded metric coefficients: male 48.0 + 2.7/in; female 45.5 + 2.2/in above 60 inches. Devine: male 50.0 + 2.3/in; female 45.5 + 2.3/in above 60 inches. No frame-size adjustment is applied.
Full precision is retained during calculation; displayed weights are rounded to one decimal place. These historical equations are reference estimates, not target weights.
Frequently asked questions
Why is adjusted weight used?
Some medicine-specific protocols use an intermediate weight between ideal and actual weight. The equation adds a selected fraction of the difference to IBW. It does not calculate a medication dose.
Hamwi or Devine: which equation?
Use the equation specified by the relevant clinical protocol. This example uses the rounded metric Hamwi coefficients. Devine is available for comparison. Neither is a direct measurement of lean body mass.
Does every medicine use AjBW?
No. Weight selection is drug-specific. Some aminoglycoside protocols use AjBW above a specified threshold. ASHP vancomycin loading-dose guidance and ASCO guidance for cytotoxic chemotherapy can use actual body weight. Confirm the exact regimen with the treating team.
What if actual weight is below IBW?
The arithmetic formula can produce an adjusted value above actual weight. That is not an instruction to increase a medication dose. AjBW is generally used for excess-weight adjustment; the appropriate dosing weight needs clinical review.
Sources & References
Body weight selection in adult antimicrobial protocols.
Vancomycin consensus guidance; dosing is drug-specific.
Guidance on body size and systemic therapy dosing.
References inform this tool; no institutional endorsement. Devine & adjusted-weight equations · Historical IBW equations and limitations.
Compare actual, ideal and adjusted weight.