BMI Calculator
Calculate your Body Mass Index, see your health category, and find your ideal weight range.
BMI Calculator – Understanding Your Body Mass Index
Body Mass Index (BMI) is one of the most widely used health screening tools worldwide. Developed in the 19th century and adopted by the WHO, it provides a quick way to assess whether a person's weight is in a healthy range relative to their height.
While BMI has limitations — particularly for athletes and elderly individuals — it remains a valuable first indicator when used alongside other health metrics like waist circumference, blood pressure, and blood glucose levels.
BMI Categories (WHO Standard)
| Category | BMI Range | Health Risk |
|---|---|---|
| Underweight | Below 18.5 | Nutritional deficiency, bone loss |
| Normal Weight | 18.5 – 24.9 | Low risk |
| Overweight | 25.0 – 29.9 | Moderate risk |
| Obese (Class I) | 30.0 – 34.9 | High risk |
| Obese (Class II+) | 35.0 and above | Very high risk |
Frequently Asked Questions
What is BMI?
BMI (Body Mass Index) is a numerical value calculated from your height and weight. It is a widely used screening tool to categorize whether a person is underweight, normal weight, overweight, or obese.
How is BMI calculated?
Metric: BMI = weight (kg) ÷ height² (m²). Imperial: BMI = 703 × weight (lbs) ÷ height² (inches²). For example, a 70 kg person at 170 cm has BMI = 70 ÷ 1.7² = 24.2.
What is a healthy BMI range?
BMI 18.5–24.9 is considered normal/healthy. Below 18.5 is underweight, 25–29.9 is overweight, and 30+ is obese. These WHO standard ranges apply to most adults.
Is BMI accurate for everyone?
BMI has limitations. It does not account for muscle mass, bone density, or fat distribution. Athletes with high muscle mass may show high BMI without being obese. It is best used as a screening tool alongside other health markers.
What are the health risks of high BMI?
Overweight and obesity are associated with increased risk of type 2 diabetes, cardiovascular disease, hypertension, sleep apnea, and certain cancers. Consult a doctor for a comprehensive health assessment.
What is the ideal weight for my height?
Ideal weight corresponds to a BMI of 18.5–24.9 for your height. Our calculator shows this range automatically once you enter your height.