Body composition calculator
BMI calculator
Get your Body Mass Index and weight category from your height and weight. Free, instant, no sign-up.
BMI is a blunt tool — the coach helps you set a goal that accounts for muscle.
What is BMI?
Body Mass Index is a simple weight-for-height ratio used as a coarse population screen for under- and overweight. It's quick to compute and universally understood — which is exactly why it's everywhere despite its limits.
How this calculator works
We divide your weight in kilograms by your height in metres squared: BMI = kg / m². Then we map it to the WHO categories — under 18.5 underweight, 18.5–25 normal, 25–30 overweight, 30 and above obese.
The catch
BMI can't tell muscle from fat. A lean, muscular lifter often reads "overweight" while carrying very little fat. For body composition, pair it with a body-fat estimate or waist measurement. Want a goal that accounts for your actual build? That's what the coach is for.