Instructions
Enter information in the height and body weight column; select appropriate gender and measurement units. Click "Calculate".
| < 18.5 | underweight |
| 18.5 to 24.9 | healthy |
| 25 to 29.9 | overweight * |
| 30 to 34.9 | grade 1 obesity |
| 35 to 39.9 | grade 2 obesity |
| >40 | grade 3 (morbid obesity) |
Body mass index (BMI) can be used to screen patients because the test is simple, correlates to fatness, and applies to both men and women. The BMI may not apply to some individuals with more than normal muscle mass and acceptable levels of body fat. In some ethnic groups, such as Pacific Islanders, BMI overestimates fatness and risk. For children and the elderly, BMI may be misleading since the muscle and bone to height relationship is changing.
* Asians are at risk with a BMI > 23 kg/m2. Pacific Islanders are at risk with a BMI > 26 kg/m2.
BMI can be used with body composition to assess fat-free mass:
- Fat-free mass is low if BMI is low and body fat is high (if =<BMI & >BF, then <FFM)
- Fat-free mass is high if BMI is high and body fat is low (if =>BMI & <BF, then >FFM)
See Waist/Hip Ratio or Body Composition Calculator for more meaningful measurements of obesity.
ACSM (2001). ACSM's Resource Manual for Guidelines for Exercise Testing and Prescription, 4th ed., pg 7.
Welborn TA, Dhaliwal SS, & Bennett SA (2003). Waist–hip ratio is the dominant risk factor predicting cardiovascular death in Australia. The Medical Journal of Australia; 179 (11/12): 580-585.
World Health Organization (1997). Obesity: preventing and managing the global epidemic. Report of a WHO consultation on obesity. Geneva.
