BMI Calculator
Calculate Body Mass Index (BMI) from height and weight, in metric or imperial units, with weight category.
About the BMI Calculator
Body Mass Index is the most widely used screening measure linking weight to height, giving a quick sense of whether someone falls into an underweight, healthy, overweight, or obese range. This calculator works in both metric and imperial units and returns your BMI along with its standard category.
How It Works
The calculator converts your height and weight to metric units if needed, then divides weight in kilograms by height in meters squared to get BMI. It compares that number against the standard World Health Organization thresholds to assign a weight category.
BMI = Weight (kg) / [Height (m)]².
Example
Scenario: A person weighing 70 kg with a height of 175 cm.
Result: BMI of about 22.9, which falls in the 'Healthy weight' category.
Assumptions & Limitations
- Uses the standard adult BMI thresholds: under 18.5 underweight, 18.5–24.9 healthy, 25–29.9 overweight, 30+ obese.
- Applies the same formula regardless of age or sex, consistent with the standard BMI definition.
- BMI does not distinguish muscle mass from fat mass, so very muscular individuals may show a higher BMI without excess body fat.
- Not designed for children, pregnant women, or elderly individuals, who need different assessment methods.