HaatBeatHow it's calculated
Metric height is converted from centimetres to metres. US height combines feet and inches. The screening category uses the unrounded result.
Assumptions
- The adult screening categories apply to people aged 20 or older. Children and teens need a different interpretation.
- Height and weight are entered as current measurements; BMI does not directly measure body fat.
- BMI is one screening measure and does not by itself describe a person’s health.
Worked example
An adult weighing 70 kilograms at 175 centimetres has a BMI of about 22.9, in the healthy-weight screening category.
Questions
How is BMI calculated?
Divide weight in kilograms by height in metres squared. In US units, use pounds and inches with the standard factor of 703.
Can I use this for a child or teenager?
No. For people under 20, BMI is interpreted using age- and sex-specific references, which this page does not calculate.
Does BMI measure body fat?
No. BMI compares weight with height. It may not reflect body composition, including high muscle mass, and should be considered alongside other health information.
Why can metric and US results differ slightly?
The US formula uses a rounded conversion factor, and entered measurements may be rounded when switching units.