What does a BMI of 31.9 mean at 5'3"?
According to the WHO/NHS standard BMI classification, a Body Mass Index of 31.9 is in the Obese Class I band. At a height of 5'3" (about 160 cm), the official healthy weight range is 47.4–63.8 kg (104.5–140.7 lbs, or roughly 7 st 7 lb to 10 st 1 lb).
A weight of 180 lbs (81.6 kg) is 17.8 kg above the top of the healthy range.
A BMI above the healthy range increases the risk of cardiometabolic conditions over time. Small, sustainable changes work best: a 500-kcal daily deficit (around 0.5 kg lost per week), 150 minutes of moderate activity, and improved sleep. See our calorie calculator and reverse BMI calculator to set a target weight.
Key facts
- BMI is a screening tool, not a diagnosis. It works well for most adults but does not distinguish between muscle and fat.
- If you are very muscular or athletic, your BMI may overestimate body fat. Pair this result with a body fat percentage check.
- For South Asian, Chinese, or Black ethnic groups, NICE recommends lower thresholds (overweight at BMI 23, obese at BMI 27.5).
- For pregnancy, use our pregnancy BMI calculator with pre-pregnancy weight instead.
- For children and teens, use the child BMI calculator with age-and-sex percentile bands.