1. 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 a person's weight in kilograms and m² is their height in meters squared. BMI provides a reliable indicator of body fatness for most people and is used to screen for weight categories that may lead to health problems.

2. How BMI is Calculated

The calculator uses the standard BMI formula:

Where:

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

Example: For a person weighing 70 kg and 1.75 m tall:
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: BMI categories may differ for some populations (e.g., Asian populations may have different cutoff points).

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 doesn't directly measure body fat. It may overestimate body fat in athletes and underestimate it in older adults with lost muscle mass.

Q2: What are the limitations of BMI?
A: BMI doesn't account for muscle mass, bone density, overall body composition, or racial/ethnic differences in body fat distribution.

Q3: Should children use this calculator?
A: No, children and teens need age- and sex-specific percentiles rather than the adult categories shown here.

Q4: What's a healthy BMI range?
A: For most adults, 18.5 to 24.9 is considered healthy, but individual health factors should also be considered.

Q5: How often should I check my BMI?
A: Periodic checks (e.g., annually) can help monitor weight status, but more frequent checks aren't typically needed unless making significant lifestyle changes.