BMI for 171 cm and 52 kg
BMI 17.8
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 64.3 kg.
The healthy range (BMI 18.5–22.9) is 54.1–67 kg.
That is 2.1 kg below the bottom of the range.
Other pairs that also give BMI 17.8
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.