BMI Calculator
Work out your Body Mass Index and the healthy weight range for your height in seconds.
BMI is a general guide, not a diagnosis. It does not account for muscle mass, bone density, age, gender or ethnicity. Consult a healthcare professional for personalized advice.
What is it
BMI (Body Mass Index) is a simple number that relates your weight to your height: weight in kilograms divided by the square of height in meters. It’s a screening tool that gives a rough idea of whether your weight sits in a healthy range — it does not measure body fat directly.
Notes & fun facts
BMI is a handy shortcut, but it has famous blind spots. It can’t tell muscle from fat, so a bodybuilder at 8% body fat can still be labelled “overweight”. It’s a starting point, not a verdict — pair it with waist size and other indicators for a fuller picture.
Origin & history
The idea dates to the 1830s, when Belgian statistician Adolphe Quetelet, busy hunting for the “average man”, noticed that weight grows roughly with the square of height. His 1832 formula was known as the Quetelet Index for more than a century, until physiologist Ancel Keys renamed it “body mass index” in 1972 and showed it works well at population level. The WHO adopted it as a standard screening tool in the 1980s.