BMI Calculator

Understanding BMI

What is BMI?

Body Mass Index (BMI) is a simple calculation using a person's height and weight. The formula is: BMI = kg/m² where kg is weight in kilograms and m is height in meters.

BMI Categories

• Underweight: BMI less than 18.5
• Normal weight: BMI 18.5 to 24.9
• Overweight: BMI 25 to 29.9
• Obese: BMI 30 or greater

Manual Calculation

1. Convert height from cm to meters (divide by 100)
2. Square the height (height × height)
3. Divide weight by height squared
Example: 70kg and 170cm (1.7m)
1.7 × 1.7 = 2.89 m²
70 ÷ 2.89 = 24.2 BMI

Limitations of BMI

• Doesn't distinguish between muscle and fat
• May underestimate body fat in older adults
• May overestimate body fat in athletes
• Doesn't account for fat distribution

Healthy Weight Range

For height 170cm (1.7m):
Normal BMI range: 18.5 to 24.9
Healthy weight range: ≈53.5kg to 72kg