Your BMI, with honest context
Enter your height and weight — metric or imperial — and get your body mass index with the standard adult categories. No data is stored or sent anywhere; the calculation happens on your device.
Frequently asked questions
How is BMI calculated?
Weight in kilograms divided by height in meters squared (kg/m²). Imperial inputs are converted automatically.
What are the BMI categories?
Under 18.5 is underweight, 18.5–24.9 healthy weight, 25–29.9 overweight, and 30+ obesity, per WHO and CDC definitions for adults.
What are BMI's limitations?
BMI doesn't distinguish muscle from fat, so athletes can read as overweight, and it doesn't apply to children, pregnancy, or the very elderly. It's a population screening number, not a diagnosis — talk to a doctor about what's healthy for you.