body mass index

American  

[bod-ee mas in-deks] / ˈbɒd i ˌmæs ˌɪn dɛks /

noun

1. an index for assessing overweight and underweight, obtained by dividing body weight in kilograms by height in meters squared: a measure of 25 or more is considered overweight.

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body mass index British  

noun

1.  BMI.  an index used to indicate whether a person is over- or underweight. It is obtained by dividing a person's weight in kilograms by the square of their height in metres. An index of 20–25 is normal

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body mass index Scientific  

/ bŏd′ē /

1. A measurement of the relative percentages of fat and muscle mass in the human body, in which weight in kilograms is divided by height in meters squared. The result is used as an index of obesity.

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Etymology

Origin of body mass index

First recorded in 1955–60

Example Sentences

Scientists are now locked in a fierce debate over the body mass index, and that could change who qualifies for a GLP-1 medication.

From MarketWatch • Mar. 18, 2026

The standard way of categorising people's weight is by calculating their body mass index, or BMI.

From BBC • Feb. 24, 2026

The decision, which was made on Jan. 6 and announced Friday, applies to patients with a body mass index of at least 30, it said.

From The Wall Street Journal • Jan. 16, 2026

Kids of all genders with higher polygenic risk scores have been shown to have higher body mass index and increased fat mass.

From Slate • Sep. 19, 2025

Food intake predicts body mass index according to a monotonically increasing relation.

From "The Sense of Style" by Steven Pinker