There’s a gap between the “gold price” reported on the daily news and the Hong-Kong-dollar price tag you see at a gold shop — bridged by unit conversion and exchange rates. Once you understand how international gold prices are quoted, you can estimate for yourself whether local prices are reasonable and trade with a clearer budget.
International Gold Is Priced in US Dollars per Troy Ounce
The international gold market uses US dollars per troy ounce as the standard quoting unit. One troy ounce equals 31.1035 grams — about 10% heavier than the avoirdupois ounce (approx. 28.35 g) used for everyday goods. When buying gold, “ounce” always refers to the troy ounce.
Gold prices come in two tiers:
- Spot price: The market price for immediate delivery, constantly moving with global trading throughout each trading day — the basis for all other quotes.
- LBMA Gold Price (London fix): Authorised by the LBMA (London Bullion Market Association) and administered by ICE Benchmark Administration, set twice daily via electronic auction at 10:30 a.m. and 3:00 p.m. London time. It is the international benchmark for mining contracts, ETF valuations, and central-bank reserve accounting.
Unit Conversion: Ounces, Grams, and Taels
Hong Kong gold shops traditionally weigh in taels (tael of the troy system). Conversions between taels, international ounces, and metric grams:
| Unit | Equals (grams) | Approximately |
|---|---|---|
| 1 troy ounce | 31.1035 g | ≈ 0.831 tael |
| 1 tael | 37.429 g | ≈ 1.203 troy ounces |
| 1 gram | 1 g | ≈ 0.0322 troy ounces |
When reading international quotes, remember: the price is “per ounce,” not “per tael” or “per gram.” Comparing them directly would produce a discrepancy of more than 10%.
Estimating the Local HK-Dollar Gold Price from International Prices
The formula for estimating the local price is straightforward:
HK-dollar gold price per gram ≈ international price (USD/oz) × USD-to-HKD exchange rate ÷ 31.1035
Because the Hong Kong dollar is pegged to the US dollar, the exchange rate is relatively stable under the linked exchange-rate system, so international gold-price movements are broadly reflected in HK-dollar prices. Minor exchange-rate fluctuations still cause small differences. Likewise, the per-tael price is simply the per-gram price multiplied by 37.429.
Key Factors That Move Gold Prices
Gold prices fluctuate daily, driven mainly by these forces:
- US-dollar trends: Gold is priced in dollars; when the dollar weakens, gold becomes cheaper in other currencies, often pushing the price up.
- Interest-rate levels: Gold pays no interest; rising rates increase the opportunity cost of holding gold, while falling rates tend to favour gold prices.
- Safe-haven demand: Geopolitical tension or financial-market turmoil drives capital into gold as a safe haven.
- Central-bank purchases: Reserve increases or decreases by central banks are a significant source of long-term demand in the gold market in recent years.
One final note: the buy and buyback prices posted by shops include a buy-sell spread and are not identical to the international spot price. Everything is subject to the day’s posted prices and on-the-spot quotes. If you’d like to know what your gold is worth at today’s price, feel free to visit our shop for a free enquiry or test — we’ll walk you through it item by item.
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