Body Mass Index (BMI) and Body Surface Area (BSA)

Usage

BMI may be a simple and cost-effective measure of body fat. BMI evaluates the relationship of body mass to height, but it may not be accurate for everyone. BMI does not differentiate between the ratio of body fat to muscle present in body mass nor factor gender, developmental or ethnic considerations. Examples of BMI Limitations:

• May be an inappropriate measure for muscular or fit body types. Body fat measurements may be more accurate.
• Ethnic variations in height and stature.

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Summary

BMI offers a more accurate understanding of body composition than weight alone. Additionally, BSA is used in specific therapeutic use cases, such as the treatment of burns.

 

Rules

• Body mass index (kg/m²) = weight(kg) / (height(m))²
• Body surface area (m²) = (Height (cm) x Weight (kg)  / 3600)^0.5
• Uses the Mosteller formula

 

 

BMI (kg/m²)	Weight
<18.5	Underweight
18.5-24.9	Normal Weight
25.0-29.9	Overweight
30.0-34.9	Obese Class 1
35.0-39.9	Obese Class 2
≥40.0	Obese Class 3

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