What does a BMI of 16.1 mean at 5'6"?
According to the WHO/NHS standard BMI classification, a Body Mass Index of 16.1 is in the Underweight band. At a height of 5'6" (about 168 cm), the official healthy weight range is 52–70 kg (114.6–154.3 lbs, or roughly 8 st 3 lb to 11 st 0 lb).
A weight of 100 lbs (45.4 kg) is 6.6 kg below the bottom of this healthy range.
A BMI in the underweight band may indicate undernutrition, an underlying medical issue, or insufficient calorie intake. A small calorie surplus, strength training, and a GP review can help. See our calorie calculator to find your daily target.
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.