BMI Calculator
Calculate Body Mass Index from your weight and height, with the WHO adult category and its real limitations explained — instantly, in your browser.
Calculate Body Mass Index from your weight and height, with the WHO adult category shown alongside. Enter your weight and height below — the result updates instantly, entirely in your browser.
Formula
BMI = weight (kg) ÷ height (m)², the standard formula used by the WHO and CDC. Worked example: 70 kg at 1.75 m: 70 ÷ (1.75 × 1.75) = 22.9.
Adult BMI categories (WHO): under 18.5 underweight, 18.5–24.9 normal weight, 25–29.9 overweight, 30+ obese.
Limitations: BMI is a population-level screening tool, not a diagnosis. It doesn’t distinguish muscle mass from fat, and the standard adult bands aren’t valid for children, teenagers, pregnant people, or highly muscular individuals. This tool is informational, not medical advice.
FAQs
Is BMI an accurate measure of health?
It’s a useful screening tool at a population level, but it doesn’t account for muscle mass, bone density, or body fat distribution — two people with the same BMI can have very different body compositions and health profiles.