BMI Calculator
betaThis free BMI calculator works out your Body Mass Index from your height and weight, tells you which category it falls in (underweight, normal, overweight or obese), and shows the healthy weight range for your height. It supports both metric and imperial units and calculates everything in your browser.
Work out your Body Mass Index from your height and weight. Everything is calculated in your browser — nothing is sent anywhere.
How to use BMI Calculator
- 1 Choose Metric or Imperial units.
- 2 Enter your height and your weight.
- 3 Read your BMI and category, shown instantly.
- 4 Check the healthy weight range for your height below the result.
Frequently asked questions
Is my data sent anywhere?
No. The calculation runs entirely in your browser — your height and weight never leave your device.
How is BMI calculated?
BMI is your weight in kilograms divided by your height in metres squared (kg/m²). The tool converts imperial units for you.
What do the categories mean?
BMI under 18.5 is underweight, 18.5–24.9 normal, 25–29.9 overweight, and 30+ obese. These are general guidelines and do not account for muscle mass or body composition.
Is BMI accurate for everyone?
BMI is a quick screening number, not a diagnosis. It can misclassify athletes and very muscular people. Treat it as a rough guide and consult a professional for advice.