BMI Calculator

What BMI measures — and what it doesn't

BMI divides weight by height squared (kg/m²) to place adults on the WHO scale: under 18.5 underweight, 18.5-24.9 healthy, 25-29.9 overweight, 30+ obese. It's a useful population-level screening number and a decent personal starting point — but it's blind to body composition: muscular people can read "overweight" while carrying little fat, and low muscle mass can hide higher fat levels inside the "healthy" band.

Treat it as one signal alongside others: waist circumference, activity level and how you actually feel. The healthy-range line in the results shows the weight span that would put your height in the 18.5-24.9 band — useful as a target zone, not a prescription.