BMI Calculator
Body mass index for adults, with the healthy weight range for your height.
BMI is a quick screening measure, not a diagnosis. It does not tell muscle from fat, so it can mislead for athletes, older adults and during pregnancy. It is for adults: children's and teenagers' BMI is judged against growth charts for their age and sex. A doctor or nurse can give advice that fits you.
How this is calculated
Categories for adults (WHO and CDC)
- Under 18.5: underweight
- 18.5 to under 25: healthy weight
- 25 to under 30: overweight
- 30 and over: obesity, in classes from 30, 35 and 40
Lower thresholds
People of South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean family background have a higher risk of conditions such as type 2 diabetes at a lower BMI. NICE recommends treating 23 as the start of overweight and 27.5 as the start of obesity for them.
Waist-to-height ratio
Waist ÷ height, in the same units. NICE guidance: 0.4 to 0.49 is healthy, 0.5 to 0.59 means increased health risk, and 0.6 or more means high health risk. It reflects fat around the middle, which BMI misses. It is intended for adults with a BMI under 35.