BMI Calculator (Metric & Imperial)
Calculate your Body Mass Index from height and weight in metric or imperial units, with the WHO category and healthy weight range for your height.
What BMI does and doesn't tell you
Body Mass Index is weight (kg) divided by height (m) squared — a quick population-level screen the WHO buckets as underweight (<18.5), healthy (18.5–24.9), overweight (25–29.9) and obesity (30+). It's useful as a first look and for tracking trends, but it can't see body composition: muscular people score "overweight" with low body fat, and the healthy thresholds vary somewhat by age and ethnicity. Treat it as one signal, not a verdict — waist measurement and a clinician's assessment complete the picture.
Frequently asked questions
Is BMI accurate for athletes?
Often not — muscle is denser than fat, so muscular builds push BMI up without excess fat. Body-fat percentage or waist-to-height ratio serve athletes better.
Is this medical advice?
No — it's an informational calculator using WHO categories. Consult a healthcare professional about your individual situation.