BMI Calculator
Body Mass Index in metric or imperial — updates as you type.
Your BMI
—
How BMI is calculated
Body Mass Index is a simple ratio of weight to height. In metric units:
BMI = weight (kg) ÷ height (m)²
In imperial units: BMI = 703 × weight (lb) ÷ height (in)².
BMI categories (adults)
| Category | BMI range |
|---|---|
| Underweight | Below 18.5 |
| Healthy weight | 18.5 – 24.9 |
| Overweight | 25.0 – 29.9 |
| Obesity | 30.0 and above |
BMI is a general guide and does not account for muscle mass, body composition or other factors. It is not medical advice — consult a healthcare professional for personal guidance.
BMI FAQ
How is BMI calculated?
BMI equals weight in kilograms divided by height in meters squared (kg/m²). In imperial units it is 703 × pounds ÷ inches².
What is a healthy BMI range?
For most adults a BMI of 18.5 to 24.9 is considered a healthy weight. BMI is a general guide and does not account for muscle mass or body composition.
Recently used