How the gram price is derived
Although Hong Kong shops quote per gram, the global market quotes gold in US dollars per troy ounce. One troy ounce equals exactly 31.1034768 grams, so the pure gold (24K) gram price is the ounce price divided by 31.1034768, converted to HKD at the live exchange rate. Lower purities are then a simple multiplication: 22K/916 is the 24K gram price × 0.9167, and 18K is × 0.75.
The Chinese Gold & Silver Exchange, operating since 1910, still quotes gold in taels (one tael ≈ 37.429 grams) alongside modern gram pricing. There is no sales tax or VAT on gold in Hong Kong, keeping premiums among the lowest in Asia.