Body Mass Index Calculator

BMI Formula:

\[ BMI = \frac{weight}{height^2} \]

BMI Result:

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Body Mass Index (BMI)?

BMI is a simple index of weight-for-height that is commonly used to classify underweight, overweight and obesity in adults. It is defined as the weight in kilograms divided by the square of the height in meters (kg/m²).

2. How Does the Calculator Work?

The calculator uses the BMI formula:

\[ BMI = \frac{weight\ (kg)}{height^2\ (m)} \]

Where:

\( weight \) — Body weight in kilograms
\( height \) — Height in meters

Explanation: BMI provides a simple numeric measure of a person's thickness or thinness, allowing health professionals to discuss weight problems more objectively with their patients.

3. Importance of BMI Calculation

Details: BMI is a simple, inexpensive, and noninvasive surrogate measure of body fat. It correlates with direct measures of body fat and provides a more accurate measure than body weight alone.

4. Using the Calculator

Tips: Enter weight in kilograms and height in meters. For height, you can convert from cm to m by dividing by 100 (e.g., 175 cm = 1.75 m).

5. Frequently Asked Questions (FAQ)

Q1: What are the BMI categories?
A: Underweight (<18.5), Normal weight (18.5-24.9), Overweight (25-29.9), and Obese (≥30).

Q2: Is BMI accurate for everyone?
A: BMI may overestimate body fat in athletes and those with muscular build, and underestimate it in older persons who have lost muscle mass.

Q3: Should children use this calculator?
A: No, children and teens need age- and sex-specific percentiles because their body composition varies as they grow.

Q4: What are the health risks of high BMI?
A: Higher BMI is associated with increased risk of heart disease, stroke, type 2 diabetes, and certain cancers.

Q5: What's a healthy BMI range for adults?
A: For most adults, 18.5 to 24.9 is considered healthy, but optimal BMI may vary by ethnicity and other factors.