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BMI Calculator

Calculate adult body mass index from height and weight in metric or US units.

Atkgandcmwhat is the BMI?

BMI is a population-level adult screening measure, not a diagnosis or a direct measurement of body fat.

Body mass index—

Units

Adult screening category—

BMI 18.5–24.9 weight range—

Height—

Weight—

How BMI is calculated

Metric BMI is weight in kilograms divided by height in meters squared. US customary BMI uses weight in pounds and height in inches with a conversion factor of 703.

BMI has limitsBMI does not distinguish fat from muscle or describe fat distribution. It can be less informative for some athletes, older adults, pregnant people and others whose body composition differs from population averages.

Adult BMI screening categories

Common adult screening thresholds are below 18.5, 18.5–24.9, 25.0–29.9 and 30.0 or above. These categories are broad screening ranges and should not be treated as a medical diagnosis.

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Common questions

Is BMI a diagnosis?

No. BMI is a screening measure based only on height and weight. Health assessment requires more context.

Is this calculator for children?

No. BMI interpretation for children and teenagers is age- and sex-specific and should use pediatric growth references.

How do I enter height in US mode?

Enter total inches. For example, 5 feet 10 inches is 70 inches.