The ring size range in China is 4-26, the ring size range in Europe is 44-61, and the ring size range in the United States is 5-12, so the ring size 16 belongs to the Chinese size, and you need to check the ring size comparison table in Chinese Mainland or Hong Kong.
Mainland version ring size comparison chart
According to the table below, the circumference of the mainland version corresponding to ring size 16 is 56mm and the diameter is 17.8mm.
Hong Kong Ring Size Comparison Table
According to the table below, ring size 16 corresponds to a Hong Kong version with a circumference of 58mm and a diameter of 17.5mm.