BMI Calculator
Body Mass Index (BMI) is a quick screening number that relates your weight to your height. This calculator gives your BMI in metric or imperial units, tells you which standard weight category it falls in, and shows the healthy weight range for your height.
How it works
BMI divides your weight by the square of your height. The widely used categories are: under 18.5 underweight, 18.5–24.9 normal, 25–29.9 overweight, and 30 or above obese. It's a population-level screen, not a diagnosis.
BMI = weight (kg) / height (m)² · (imperial: 703 × lb / in²)Example. Someone 170 cm tall weighing 70 kg has a BMI of 24.2 - within the normal range, whose healthy weight band for that height is about 53.5–72.0 kg.
What BMI does and doesn't tell you
BMI doesn't distinguish muscle from fat or account for body composition, age, sex or ethnicity, so very muscular people can read as 'overweight' while the number can understate risk for others. Use it as a starting point and pair it with measures like waist circumference and a doctor's advice.
Frequently asked questions
Is BMI accurate for athletes?
Not always. Muscle weighs more than fat, so very muscular or athletic people can have a high BMI while carrying little body fat. For them, body-fat percentage is a better measure.
What is a healthy BMI?
For most adults, a BMI between 18.5 and 24.9 is considered the healthy range. Below 18.5 is underweight and 25 or above is overweight, but interpret it alongside other health indicators.
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