BMI Calculator
Calculate your Body Mass Index instantly. Enter your height and weight to see your BMI score and health category.
What Is BMI and Why Does It Matter?
Body Mass Index (BMI) is a simple screening tool used by healthcare professionals worldwide to assess whether a person's weight is appropriate for their height. Calculated using your weight in kilograms divided by the square of your height in metres, BMI provides a quick, cost-free estimate of body fatness that correlates with risk of chronic diseases.
BMI Formula
Example: A person weighing 70 kg with a height of 1.75 m has a BMI of 70 ÷ (1.75 × 1.75) = 22.86 — squarely in the Normal range.
BMI Categories (WHO Standard)
- Underweight (BMI < 18.5): May indicate nutritional deficiency or underlying illness. A doctor's evaluation is recommended.
- Normal weight (18.5–24.9): Associated with the lowest risk of weight-related health problems.
- Overweight (25–29.9): Increased risk of cardiovascular disease, type 2 diabetes, and joint problems.
- Obese (≥30): Significantly elevated risk of serious conditions including heart disease, stroke, and certain cancers.
Limitations of BMI
BMI does not distinguish between fat and muscle mass — highly trained athletes may register as overweight. It also doesn't account for age, sex, ethnicity, or fat distribution. Always interpret BMI alongside lifestyle factors and consult a qualified healthcare professional for personalized advice.
Who Should Use This Calculator?
This BMI calculator is designed for adults aged 18 and over. For children and teenagers, paediatricians use BMI-for-age percentile charts. Pregnant women should not use standard BMI calculations during pregnancy.