About this BMI calculator
BMI, short for body mass index, is a quick way to check whether your weight is roughly healthy for your height. You enter your weight and height, and the calculator gives one number plus a category — underweight, healthy weight, overweight or obese. It is a screening guide used worldwide, not a diagnosis: it does not account for muscle, bone or where fat sits on your body. Athletes, for example, can have a high BMI while being very lean. Use it as a starting point and speak to a health professional for personal advice. Everything is worked out in your browser, so your numbers stay private.
Frequently asked questions
- What is BMI?
- A single number comparing your weight to your height — a quick guide to whether your weight is in a healthy range. It does not measure body fat directly.
- How is BMI calculated?
- Metric: weight (kg) ÷ height (m)². Imperial: 703 × weight (lb) ÷ height (in)². This tool does it for you.
- What counts as a healthy BMI?
- For most adults, 18.5–24.9 is the healthy range. Under 18.5 is underweight, 25–29.9 overweight, 30+ obese. It is a guide, not medical advice.