BMI Calculator
Enter your height and weight to calculate your Body Mass Index and see which category you fall into.
BMI scale
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BMI Categories
| Category | BMI Range (kg/m²) |
|---|---|
| Underweight | < 18.5 |
| Normal weight | 18.5 – 24.9 |
| Overweight | 25.0 – 29.9 |
| Obese (Class I) | 30.0 – 34.9 |
| Obese (Class II) | 35.0 – 39.9 |
| Obese (Class III) | ≥ 40.0 |
Understanding BMI
Body Mass Index (BMI) is a simple calculation using your height and weight. The formula is weight (kg) ÷ height (m)². It was developed in the 19th century by Adolphe Quetelet and remains one of the most widely used screening tools for weight status.
Limitations of BMI
- BMI does not measure body fat directly. Two people with the same BMI may have very different amounts of body fat.
- Athletes and muscular individuals may be classified as overweight or obese despite having low body fat.
- BMI does not account for age, sex, ethnicity, or where fat is distributed (visceral vs. subcutaneous).
- For a more complete assessment, consider measuring waist circumference, body fat percentage, and metabolic markers.
What you can do
If your BMI falls outside the normal range, discuss it with your healthcare provider. They can evaluate additional factors and recommend a personalized plan that may include dietary changes, exercise, or further testing.
Frequently Asked Questions
What is BMI?+
Body Mass Index (BMI) is a numerical value calculated from your weight and height. It provides a simple screening tool to categorize weight status. The formula is: BMI = weight (kg) / height (m)².
Is BMI accurate for everyone?+
BMI does not distinguish between muscle and fat mass. Athletes or muscular individuals may have a high BMI despite low body fat. Similarly, older adults who have lost muscle mass may have a normal BMI but carry excess fat. BMI is best used as one indicator alongside other measures like waist circumference and body composition.
What is a healthy BMI?+
A BMI between 18.5 and 24.9 is generally considered healthy for most adults. However, optimal BMI can vary by age, sex, ethnicity, and body composition. Your doctor can help determine what’s right for you.
Should I rely only on BMI?+
No. BMI is a useful starting point but has limitations. Waist circumference, waist-to-hip ratio, body fat percentage, and metabolic health markers (blood pressure, cholesterol, blood sugar) provide a more complete picture of your health.
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