BMI and metabolism: different measurements
The short answer
BMI is not metabolic rate. Energy expenditure, hormone status and calories are not outputs of the BMI formula. A change in BMI cannot establish why weight changed or whether muscle or fat changed. This calculator does not prescribe calories or diagnose a metabolic condition.
BMI is not metabolic rate. Energy expenditure, hormone status and calories are not outputs of the BMI formula. A change in BMI cannot establish why weight changed or whether muscle or fat changed. This calculator does not prescribe calories or diagnose a metabolic condition.
How we calculate
Body mass index (BMI) is weight in kilograms divided by height in metres squared. It is one screening measure, not a diagnosis or a direct measurement of body fat.
Imperial inputs are converted using 1 lb = 0.45359237 kg and 1 in = 2.54 cm. Five feet nine inches is 69 inches, not 5.9 feet.
Units are converted before calculation. Categories use the unrounded result; only the display is rounded. The shortcut multiplier 703 can differ slightly from exact conversion.
Screening scope
Adult (20+), not pregnant. For ages 2–19, use a validated BMI-for-age calculator. This tool shows adult ranges only.
BMI is one screening measure, not a diagnosis or a weight goal. It does not distinguish muscle from fat and is not suitable for pregnancy.
This explanation checks the method and arithmetic. It does not claim an independent medical review. Personal interpretation requires context and an appropriate healthcare professional.
Sources
Sources below are in English.