Body mass index (BMI) is an internationally recognised standard to classify the body weight of adults. Although BMI is not a perfect measure, it is the most useful and valid for adults.
As the BMI calculation doesn’t take fat or muscle into account, you should measure your waist as well to get the full picture. BMI is not an appropriate measure for children.
Waist size showing increased risk of chronic disease
| Gender | Increased risk | Greatly increased risk |
| Men | 94 cm or more | 102 cm or more |
| Women | 80 cm or more | 88 cm or more |
Measuring your waist
To measure your waist:
- take off any bulky clothing, loosen your belt and empty your pockets.
- stand with your feet shoulder-width apart.
- wrap a tape measure around your belly – in line with your belly button, and loose enough to fit one finger inside the tape.
- These measurements do not apply to children and pregnant women.
