Body Mass Index is defined in SI units as weight (kg) / height
(m)². The metric form (kg and cm) is the most direct way to
compute it — the calculator divides your weight by your height in
metres squared with no unit conversion. This is the form used in
the WHO cut-offs, in the Deurenberg body-fat formula, in the
Mifflin–St Jeor BMR, and in most clinical guidelines.
What you get beyond BMI
Beyond the BMI value, the calculator shows your WHO category (underweight, normal, overweight, obese) with a colour-coded gauge, plus BMI Prime, Ponderal Index, body-fat percentage, healthy weight range, ideal weight (Devine), lean body mass (Boer), BMR and TDEE at five activity levels. Open the optional waist input for a waist-to-height ratio with a risk label.
Next steps
- kg + cm form (this page in different wording)
- Imperial BMI calculator (lb + ft+in)
- Asian BMI calculator with the ≥23 / ≥27.5 cut-offs