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BMI Calculator
BMI (Body Mass Index) is a quick screen that relates your weight to your height. Enter yours to see your category and healthy-weight range.
Free · no signup · updated August 2026
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How BMI works and what it means
Body Mass Index is your weight divided by the square of your height: BMI = kg ÷ m². It is a fast population-level screen for whether your weight is in a healthy range for your height. The World Health Organization bands for adults are:
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Healthy weight |
| 25.0 – 29.9 | Overweight |
| 30.0 and above | Obese |
BMI is quick but blunt: it cannot tell muscle from fat or show where fat is stored, so athletes can read high while carrying little fat. Use it as one signal alongside waist circumference and how your clothes fit, and see the TDEE and calorie-deficit calculators if you want to change it.
Frequently asked questions
What is a healthy BMI?
For adults the standard bands are: under 18.5 underweight, 18.5–24.9 healthy weight, 25–29.9 overweight, and 30 or over obese. These are population screens, not a diagnosis.
Is BMI accurate?
BMI is a useful, fast screen but it does not distinguish muscle from fat or show where fat sits. A very muscular person can read "overweight" while carrying little fat. Treat it as one signal alongside waist size, body composition and how you feel.
How do I calculate BMI myself?
BMI = weight in kilograms ÷ (height in metres)². In imperial units it is 703 × pounds ÷ (inches)². This calculator does the conversion for you.
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Estimates for general information only, not medical advice. BMR/TDEE use the Mifflin-St Jeor equation; individual needs vary.
