The BMI Calculator computes your Body Mass Index from height and weight and shows which standard category it falls in — along with the healthy weight range for your height. It is a screening number, useful for a quick check and for forms that ask for it.
What is a healthy BMI?
For adults, the standard ranges are: below 18.5 underweight, 18.5–24.9 healthy, 25–29.9 overweight, 30 and above obese. These are population guidelines — athletes with a lot of muscle can read 'overweight' while being perfectly fit.
Is BMI different for children?
Yes — children's BMI is judged against age-and-sex growth charts (percentiles), not the adult ranges. This calculator's categories are the adult standard, so treat results for under-18s as only a rough indicator.
Do I need to sign up or install anything?
No. The BMI Calculator is completely free, needs no account and nothing to install — it runs in your browser, and anything you type stays on your device.