BMI Calculator
BMI (Body Mass Index) is a number calculated from your height and weight using the formula: BMI = weight(kg) ÷ height(m)². It categorises weight as Underweight (<18.5), Normal (18.5–24.9), Overweight (25–29.9), or Obese (≥30).
What is BMI Calculator?
BMI is a widely used screening tool to categorise weight status relative to height. While it does not directly measure body fat, it correlates well with body fat measurements and is used by health professionals as a simple initial assessment. Metric BMI divides weight in kg by the square of height in metres; Imperial BMI uses: 703 × weight(lb) ÷ height(in)².
Use Cases
- Initial health screening for adults.
- Tracking weight changes over time.
- Understanding clinical weight categories.
How to Use It
Select your unit system (Metric or Imperial).
Enter your weight and height.
Your BMI and weight category are shown instantly.
Review the healthy weight range for your height.
Pros
- Simple, universally understood health metric.
- Supports both metric and imperial units.
Limitations
- Does not distinguish between muscle and fat mass.
- Less accurate for athletes, elderly, and some ethnic groups.
Best Practices
- BMI is a screening tool, not a diagnosis. Consult a doctor for medical advice.
- Athletes with high muscle mass may have high BMI despite being healthy.
- BMI thresholds differ for some ethnic groups—Asian populations use lower thresholds.
Common Mistakes to Avoid
- Using BMI as a sole measure of health—it does not account for muscle mass or fat distribution.
- Applying adult BMI categories to children (use BMI-for-age percentiles instead).
FAQs
Is BMI accurate for athletes?
Not always. Athletes with high muscle mass may have a "Overweight" BMI despite very low body fat. Use body composition measurements for a more accurate assessment.
What is a healthy BMI range?
For most adults, 18.5–24.9 is considered healthy. For people of South Asian descent, 18.5–22.9 is often recommended.