1. What is BMI?

Body Mass Index (BMI) is a simple index of weight-for-height that is commonly used to classify underweight, normal weight, 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 BMI is Calculated

The BMI formula is:

Where:

• Weight — Measured in kilograms (kg)
• Height — Measured in meters (m)

Example: For a person weighing 70 kg with height 1.75 m:
BMI = 70 / (1.75 × 1.75) = 22.9 kg/m²

3. BMI Categories

Standard BMI Categories for Adults:

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

Note: These categories may vary slightly for different populations and should be interpreted with caution in athletes and elderly.

4. Using the Calculator

Instructions: Enter your 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: Is BMI accurate for everyone?
A: BMI is a useful screening tool but has limitations. It may overestimate body fat in muscular individuals and underestimate it in older people with less muscle mass.

Q2: What's a healthy BMI range?
A: For most adults, 18.5 to 24.9 is considered healthy. However, optimal BMI may vary by age, sex, and ethnicity.

Q3: Can children use this calculator?
A: This calculator is for adults. Children's BMI is interpreted differently using age- and sex-specific percentiles.

Q4: How often should I check my BMI?
A: For most adults, checking every few months is sufficient unless you're actively trying to change your weight.

Q5: What's better than BMI for measuring health?
A: While BMI is convenient, other measures like waist circumference, body fat percentage, and metabolic tests provide more comprehensive health assessment.