Body Mass Index
All calculations should be independently verified prior to clinical use. These calculators are intended to supplement, not replace, clinical judgment.
Calculate body mass index (BMI) from weight and height, with optional unit conversion from pounds and inches.
BMI classification by sex (adult reference ranges):
| Classification | Female | Male |
|---|---|---|
| Underweight | < 19 | < 20 |
| Acceptable | 19 – 25 | 20 – 25 |
| Overweight | 25 – 30 | 25 – 30 |
| Obese | 30 – 40 | 30 – 40 |
| Morbidly obese | > 40 | > 40 |
The formula is:
where W is the weight in kilograms and H is the height in meters. Weight in pounds is converted to kg (÷ 2.2046) and height in inches to cm (× 2.54) before calculation.
For pediatric BMI interpretation by age and sex percentile, see the CDC BMI Percentile Calculator for Child and Teen.
References
- Keys A, Fidanza F, Karvonen MJ, Kimura N, Taylor HL. Indices of relative weight and obesity. J Chronic Dis. 1972;25(6):329–343.
- Centers for Disease Control and Prevention. About BMI for children and teens. Available at: https://www.cdc.gov/bmi/child-teen-calculator/index.html.