Estimated Body Weight Loss Calculator

Estimates body mass lost due to amputation


Body Mass (optional)



Ideal weight
Amputation ideal weight

Percent Above Ideal
Amputation adjusted weight

About This Calculator

Estimated body weight loss (EBWL) describes the amount of body mass lost due to an amputation. EBWL is most commonly utilized for determining an amputee's ideal body weight, which is a function of patient height. An EBWL-adjusted ideal body weight is most commonly used for determining renal function with creatinine clearance.

Estimated Body Weight Loss (EBWL) Table

The following estimates are reasonable for determining a patient's amputation ideal body weight (or adjusted body weight for overweight patients).1,2

Level of Amputation % EBWL
Foot 1.5%
Below-knee amputation (BKA) 3.5%
Above-knee amputation (AKA) 11%
Hip disarticulation 16%
Hand 0.7%
Forearm 1.5%
Entire arm 4%

Ideal and Adjusted Amputation Body Weight

For patients without amputations, an ideal body weight equation (as described by Devine 1974) is calculated according to the equation below. For patients with amputations, the EBWL is used to calculate a percent of predicted ideal body weight:3

$$ \\Ideal\;BW\;(men)\; = 50 + 2.3*(height\;over\;60\;inches) \\Ideal\;BW\;(women)\; = 45.5 + 2.3*(height\;over\;60\;inches) \\Amputation\;ideal\;BW = (1 - EBWL) * Ideal\;BW $$

Adjusted body weight

In patients who are more than 30% of an amputation ideal weight, an "amputation adjusted weight" may be used. This adjusted body weight uses an adjustment factor of 0.4 (or 40%). Adjusted body weight is commonly used for calculations like creatinine clearance.

$$ \\AdjustedBW\; = IdealBW + (0.4*(ActualBW - IdealBW)) $$

References and Additional Reading

  1. Osterkamp LK. Current perspective on assessment of human body proportions of relevance to amputees. J Am Diet Assoc. 1995 Feb;95(2):215-8. PMID 7852688.
  2. Im EE, Stewart IJ, Morrow BD, et al. Retrospective review of serum creatinine and creatinine-based measures of estimated glomerular filtration rate in an amputee population. Mil Med. 2012 Aug;177(8):952-6. PMID 22934376.
  3. Devine BJ. Gentamicin therapy. Drug Intell Clin Pharm. 1974;8:650–655.


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Updated Dec 30, 2023
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