BMI Calculator

What BMI is

Body mass index is weight divided by height squared. That is the whole formula — a 70 kg adult who is 1.75 m tall has a BMI of 70 ÷ 1.75², which is 22.9.

It was designed in the nineteenth century to describe populations, not individuals, and it survives because it is quick and needs only two numbers anyone can measure at home.

The standard bands

What BMI does not tell you

BMI cannot tell muscle from fat. A trained athlete can land in the "overweight" band while carrying very little fat, and someone can sit in the "normal" band with poor muscle mass. It also says nothing about where weight is carried, which matters more to health risk than the total does.

Several health bodies use lower thresholds for South Asian populations, where risk rises at a lower BMI than the standard bands suggest. Treat the number as one rough signal among several, and talk to a doctor rather than to a calculator about what it means for you.

Frequently Asked Questions

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