BMI Body Mass Index Calculator
What is this BMI calculator?
The BMI (Body Mass Index) calculator instantly computes your ratio of weight to height, giving a score used to screen for healthy, underweight, overweight, or obesity categories for adults. It's a quick tool for understanding your general weight status, with recognized categories based on World Health Organization standards.
How to use this BMI tool
- Enter your weight. You can change the unit (kg/lb) using the dropdown.
- Enter your height. You can use centimeters or inches.
- Click Calculate BMI to see your exact BMI value and category instantly.
- Use Reset to start again, or load the example for a quick demo.
Note: This calculator is designed for use by adults aged 18 and over.
Example input and output
| Input | BMI | Category |
|---|---|---|
| Weight: 70 kg, Height: 172 cm | 23.7 | Normal weight |
| Weight: 90 kg, Height: 165 cm | 33.1 | Obese |
| Weight: 52 kg, Height: 160 cm | 20.3 | Normal weight |
| Weight: 58 kg, Height: 180 cm | 17.9 | Underweight |
Understanding your BMI result
| BMI Value | Weight Status |
|---|---|
| < 18.5 | Underweight |
| 18.5 – 24.9 | Normal weight |
| 25.0 – 29.9 | Overweight |
| 30.0 or above | Obese |
BMI is a standard screening measure. However, muscle mass, pregnancy, age, and body composition also affect health—always use with clinical context. The tool does not provide medical advice.
FAQ about BMI calculator
- What does my BMI mean?
- Your BMI indicates which general weight category you fall into (underweight, normal, overweight, or obese) for adults. It's a rough indicator and not a full picture of personal health.
- Can children or teenagers use this tool?
- No. BMI calculation and categories for those under 18 use age and sex, which this tool does not support.
- Is BMI a perfect measure of health?
- No. While BMI is widely used for screening, it doesn't distinguish between muscle, fat, and other tissue. For many (athletes, older adults, pregnant people), BMI interpretation may differ.
- What units does the calculator accept?
- You may enter weight in kilograms (kg) or pounds (lb), and height in centimeters (cm) or inches (in). Calculations are adjusted automatically.
- Will my data be saved?
- No input is saved or sent anywhere. Calculations run only in your browser for privacy.