BMI for 173 cm and 51 kg
BMI 17
Asia-Pacific cut-offs (23 · 25) · underweight
WHO international cut-offs (25 · 30) · underweight
Reference weight and healthy range
At BMI 22 the reference weight is 65.8 kg.
The healthy range (BMI 18.5–22.9) is 55.4–68.5 kg.
That is 4.4 kg below the bottom of the range.
Other pairs that also give BMI 17
Nearby heights and weights
BMI cannot tell muscle from fat, so it reads high for people who train heavily. It is a reference figure, not a diagnosis.