Adult BMI Calculator

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A screening number.
Not your whole story.

Calculate body mass index from height and weight, then see what the result can and cannot tell you.

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For adults aged 20 and older. Enter your measurements; changing units converts them.

For imperial height, 6 feet = 72 inches; 6 feet 7 inches = 79 inches. Age checks eligibility and is not part of the formula.

Enter your details, then calculate.

How BMI is calculated

BMI = weight in kilograms ÷ height in metres squared. Imperial measurements are converted before calculation. BMI categories below apply to adults aged 20 and older.

Standard adult BMI screening categories
BMICategory
Below 18.5Underweight
18.5 to below 25Healthy weight
25 to below 30Overweight
30 or aboveObesity

The category uses the unrounded result; the displayed BMI rounds to one decimal place. A value very close to a boundary may round to the next category’s starting number.

Muscle changes the interpretation

BMI does not measure body fat or distinguish muscle from fat. A muscular person may have a higher BMI without the same body composition as another person at that BMI.

Consider the result alongside waist measurements, health history, and an individual assessment. A screening category is not a diagnosis or a target weight recommendation. This tool is not intended to interpret pregnancy, significant fluid retention, or limb loss.

Source: CDC adult BMI categories

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