Body mass index (BMI) is a quick screening number based on height and weight. Enter yours in US or metric units to see your BMI, its category, and the healthy weight range for your height.
How to use this calculator
- Choose US or metric units.
- Enter your height and weight.
- Read your BMI and category.
How it's calculated
BMI = weight (kg) ÷ height (m)²
In US units: BMI = 703 × weight (lb) ÷ height (in)². Adult categories (CDC): under 18.5 underweight, 18.5–24.9 healthy, 25–29.9 overweight, 30 and above obesity.
Frequently asked questions
Is BMI accurate?
BMI is a useful screening tool for populations, but it doesn't measure body fat directly. Very muscular people can have a high BMI while being healthy. It isn't a diagnosis.
Is this calculator for children?
No. Children's and teens' BMI is interpreted with age- and sex-specific percentiles. Ask a pediatrician.
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