5.4cm refers to a ring circumference of 54mm. Currently, there are four mainstream ring size standards in the market: Hong Kong version ring size, mainland version ring size, American version ring size, and European version ring size. The specific selection needs to be based on the comparison table used by the store.
Mainland version ring size comparison chart
According to the table below, the ring with a circumference of 54mm corresponds to the mainland version size 14 and a diameter of 17.2mm.
Hong Kong Ring Size Comparison Table
According to the table below, the ring with a circumference of 54mm corresponds to the Hong Kong version number 12 and a diameter of 16.2mm.
US Ring Size Comparison Table
According to the table below, the ring with a circumference of 54mm corresponds to a US size of around 7 and a diameter of 17.3mm.
European Ring Size Comparison Table
According to the table below, the ring with a circumference of 54mm corresponds to the European size 54 and a diameter of 17.19mm.