BMI is a screening estimate for adults age 20 and older. It is not a diagnosis or a substitute for professional medical advice. BMI does not directly measure body fat and should be considered alongside other health factors. If you have health questions, speak with a qualified healthcare provider.
Frequently asked questions
Common questions about BMI
Everything you need to know about using our BMI calculator.
Is BMI a diagnosis?
No. BMI is a screening measure. Individual health assessment may include body composition, medical history, examination, and other measures.
Does the calculator support pounds and feet?
Yes. Choose Imperial, then enter pounds plus feet and inches. Inches must be less than 12.
Why is height squared in the BMI formula?
Squaring height is part of the BMI definition and scales weight relative to body size more usefully than dividing by height alone.
Can I use adult BMI categories for a child?
No. Children and teens use age- and sex-specific BMI percentiles, not the fixed adult cutoffs shown here.
Why can a muscular person have a high BMI?
BMI uses total weight and cannot distinguish muscle from fat, so greater muscle mass can raise the result.