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Calculation Machine

Adjusted Body Weight Calculator

Ideal and adjusted body weight from height, actual weight and sex.

Updated · How we check our maths

Your values

0.4 is standard; some protocols use 0.3–0.5.

Results
Adjusted body weight
89.2 kg (196.6 lb)
Ideal body weight (Devine)
73.0 kg (160.9 lb)
Actual body weight
113.4 kg (250.0 lb)
Actual ÷ ideal
155%
Note
Over 120% of IBW — AjBW commonly used

Quick answer

Adjusted body weight = IBW + 0.4 × (actual weight − IBW), where ideal body weight (Devine) is 50 kg + 2.3 kg per inch over 5 ft for men and 45.5 kg + 2.3 kg per inch for women. A 5′10″ man weighing 250 lb has an IBW of 73 kg and an AjBW of about 89 kg (196 lb).

What the Adjusted Body Weight Calculator does

Clinicians use adjusted body weight for some drug doses (for example aminoglycosides) and nutrition estimates in people with obesity, because neither actual nor ideal weight reflects how those drugs distribute. The calculator applies the Devine IBW formula and the standard 0.4 correction factor, and shows both in kg and lb.

This is an educational tool: dosing decisions must follow your clinical protocol and a qualified professional.

The formula

IBW (male) = 50 + 2.3 × (height in inches − 60); IBW (female) = 45.5 + 2.3 × (height in inches − 60).

AjBW = IBW + 0.4 × (ABW − IBW)

Worked example

Female, 165 cm (65 in), 100 kg: IBW = 45.5 + 2.3 × 5 = 57 kg; AjBW = 57 + 0.4 × 43 = 74.2 kg.

How to use the Adjusted Body Weight Calculator

  1. Choose sex and units.
  2. Enter height and actual weight.
  3. Keep the 0.4 factor unless your protocol says otherwise.

Frequently asked questions

When is adjusted body weight used?

Typically when actual weight is more than 120–130% of ideal body weight, for certain drug doses and energy-needs calculations.

What formula is used for ideal body weight?

The Devine formula, the most common in clinical practice.

Does it work for people under 5 feet?

The Devine formula is not validated below 60 inches; results there are unreliable.

Results are estimates for planning and learning. Check important figures with a qualified professional. How we build and check our calculators.