BMI Calculator
Estimate body mass index from height and weight. Learn how the calculation works and why BMI alone does not assess individual health.
BMI Calculator
<18.5 Normal
18.5-24.9 Overweight
25-29.9 Obese
30+
Calculate BMI from height and weight
Choose US or metric units and enter the requested measurements. Select Calculate and read the result with its unit labels. Clear resets the form. Check the original measurements and selected units if a value looks unexpected.
A worked example
For a person weighing 70 kilograms at a height of 1.75 meters, BMI is 70 divided by 1.75 squared, or about 22.9. This is a calculation example, not an assessment of any particular reader’s health.
What the result can tell you
BMI relates weight to height and is used as a screening measure. It does not directly measure body fat or distinguish fat, muscle, and bone. The CDC explains BMI’s uses and limitations, including the need to consider medical history and other health measures.
Use the appropriate assessment
Adult ranges do not replace age- and sex-specific assessment for children and teens. Other values shown here, such as BMI Prime or Ponderal Index, are calculated measures rather than a diagnosis. Discuss concerns about weight or changes in health with a qualified clinician rather than setting treatment or dietary goals from a color-coded result alone.