How the gram price is derived
Although European 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 EUR 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.
European bullion dealers quote in euros per gram, per 100 grams, and per ounce. Under the EU investment gold directive, gold of at least 995 fineness in bar form (and qualifying coins) is exempt from VAT throughout the European Union.