BMI Calculator
Calculate your Body Mass Index (BMI) instantly with metric or imperial units. Understand what your BMI means and its limitations. Free, evidence-based.
All calculations run instantly in your browser. No data is sent to any server.
Disclaimer: Results are for informational purposes only and do not constitute medical advice, diagnosis, or treatment. Consult a qualified healthcare professional for personal guidance.
What BMI Measures — and What It Doesn't
BMI (Body Mass Index) = weight (kg) ÷ height² (m²). It is a population-level screening tool, not a clinical diagnostic. Its primary limitation is that it cannot distinguish muscle mass from fat mass — a trained athlete may register as overweight while carrying very low body fat. For individual health assessment, BMI should be combined with waist circumference (a better proxy for visceral fat) and, ideally, body fat percentage measurement.
Ethnic-Specific Thresholds
The WHO and NHS recommend lower BMI thresholds for South Asian, Chinese, and Japanese populations, who show elevated metabolic risk at BMIs above 23 (vs. 25 for European populations). If you are of South or East Asian heritage, discuss appropriate targets with your GP.
FAQs
What is a healthy BMI?
WHO: 18.5–24.9 for adults. Note: South/East Asian adults face elevated metabolic risk at lower thresholds (≥23).
What are BMI's limitations?
Doesn't measure body fat or its distribution. Muscular individuals may be misclassified. Use with waist circumference for better risk assessment.