BMI Calculator Body Mass Index And BSA

Formulas:

\[ BMI = \frac{W}{H^2} \] \[ BSA = \sqrt{\frac{W \times H}{3600}} \]

BMI (kg/m²):

BSA (m²):

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1. What is BMI and BSA?

BMI Definition: Body Mass Index (BMI) is a measure of body fat based on height and weight that applies to adult men and women.

BSA Definition: Body Surface Area (BSA) is the calculated surface area of the human body, often used in medical calculations.

Purpose: These measurements help assess health risks, determine medication dosages, and evaluate nutritional status.

2. How Does the Calculator Work?

The calculator uses two formulas:

\[ BMI = \frac{Weight\ (kg)}{(Height\ (m))^2} \] \[ BSA = \sqrt{\frac{Weight\ (kg) \times Height\ (cm)}{3600}} \]

Where:

BMI — Body Mass Index (kg/m²)
BSA — Body Surface Area (m²)
Weight — in kilograms (kg)
Height — in centimeters (cm) for BSA, converted to meters (m) for BMI

3. BMI Categories

Underweight: BMI < 18.5
Normal weight: BMI 18.5-24.9
Overweight: BMI 25-29.9
Obesity: BMI ≥ 30

4. Using the Calculator

Tips: Enter your weight in kilograms and height in centimeters. The calculator will automatically compute both BMI and BSA.

5. Frequently Asked Questions (FAQ)

Q1: Why are different height units used for BMI and BSA?
A: BMI traditionally uses meters while BSA calculations typically use centimeters. The calculator handles the conversion automatically.

Q2: Is BMI accurate for athletes?
A: BMI may overestimate body fat in muscular individuals as it doesn't distinguish between muscle and fat mass.

Q3: What is BSA used for?
A: BSA is used to calculate medical indicators, drug dosages, and for assessing burn victims.

Q4: Can I use pounds and inches?
A: This calculator uses metric units. For imperial units, convert weight to kg (1 lb = 0.453592 kg) and height to cm (1 inch = 2.54 cm).

Q5: What's a normal BSA range?
A: Average BSA is about 1.7 m² for adult men and 1.6 m² for adult women, but varies with body size.