Adjusted Body Weight Calculator

What is Adjusted Body Weight?

Adjusted Body Weight (AjBW) is a calculated measure used in clinical and nutritional settings, particularly for individuals who are overweight or obese. It provides a more accurate estimate for determining a person's nutritional needs (like calorie and protein requirements) and for calculating medication dosages than using actual body weight or ideal body weight alone.

The rationale behind using AjBW is that lean body mass is more metabolically active than fat mass. For an obese individual, using their actual body weight can lead to overestimation of calorie needs or medication dosages, while using their ideal body weight can lead to underestimation. Adjusted body weight provides a middle ground.

How to Calculate Adjusted Body Weight

The calculation requires two primary inputs: Ideal Body Weight (IBW) and Actual Body Weight (ABW). First, you must calculate the IBW, typically using a standard formula like the Devine formula:

• For Males: IBW (kg) = 50 kg + 2.3 kg for each inch over 5 feet.
• For Females: IBW (kg) = 45.5 kg + 2.3 kg for each inch over 5 feet.

Once you have the IBW, the formula for Adjusted Body Weight is:

AjBW = ((ABW - IBW) × 0.4) + IBW

This formula essentially takes the ideal body weight and adds 40% of the "excess" weight (the difference between actual and ideal weight). Our calculator automates this entire process for you.

Frequently Asked Questions (FAQ)

Q: Should I use Adjusted Body Weight for my own diet?

A: While you can, it's generally a tool for clinical use. For general weight loss, focusing on a sustainable calorie deficit based on your Total Daily Energy Expenditure (TDEE), which is calculated from your actual body weight, is a more common and effective approach. AjBW is for refining professional calculations.

Q: Why is the correction factor 0.4 (or 40%)?

A: The 40% factor is a widely accepted clinical estimate. It represents the assumption that excess body weight in an obese individual is approximately 40% metabolically active lean tissue and 60% less active adipose tissue. Different correction factors (e.g., 25%) are sometimes used, but 40% is the most common standard.

Q: Is this calculator a substitute for professional medical advice?

A: No. This calculator is for informational purposes only. All medical and nutritional decisions, especially regarding medication dosage, should be made by a qualified healthcare professional.