BMI Calculator

BMI Calculator

Estimate body mass index and see the standard adult screening range.

UNDERSTAND THE ANSWER

How is this calculated?

BMI is a population-level screening measure. It does not directly measure body fat, fitness or health and can be misleading for some people.

BMI formula for US unitsBMI = 703 × weight (lb) ÷ height² (in)

A practical example

A person who is 5 ft 10 in and weighs 170 lb has a BMI of about 24.4.

Assumptions, interpretation and common mistakes

Calculation assumptions

  • The adult US-unit BMI formula is used.
  • Height and weight are entered accurately without adjustment for clothing.
  • Adult reference ranges are used and may not apply to children or pregnancy.

How to interpret the result

  • BMI is a screening ratio, not a direct body-fat measurement.
  • The reference weight range corresponds only to standard BMI thresholds for the entered height.
  • Individual risk depends on factors BMI does not measure.

Common mistakes to avoid

  • Using BMI as a diagnosis or personal health verdict.
  • Applying adult cutoffs to children or adolescents.
  • Ignoring muscle mass, pregnancy, age, ethnicity and fat distribution.