Whether you’re buying bullion, tracking gold prices, or just curious about the terms you see in precious metal markets, the phrase “troy ounce” pops up everywhere. But what exactly is a troy ounce, where did it come from, and how does it compare to the weights we use every day in Australia? Here’s everything you need to know for 2025 and beyond.
A troy ounce is a traditional unit of measurement used specifically for precious metals like gold, silver, platinum, and palladium. Unlike the more familiar “avoirdupois” ounce (used for groceries and most other goods), the troy ounce is slightly heavier. One troy ounce equals approximately 31.1035 grams, compared to 28.3495 grams for a standard ounce.
This difference might seem small, but in gold and silver trading, it adds up quickly—impacting price quotes, investment decisions, and even taxation.
The troy ounce traces its roots back to the medieval French city of Troyes, a bustling trading hub in the Middle Ages. Merchants across Europe needed a reliable, standardised weight for valuable commodities, and the “troy” system fit the bill. Adopted by the British Empire in the 1400s, the troy ounce became the global standard for precious metals.
Australia, following British conventions, also embraced the troy ounce for its gold rush era and beyond. Today, the troy ounce remains the backbone of bullion and coin markets worldwide—even as digital trading and metric weights gain traction. Notably, the London Bullion Market Association (LBMA) and the Perth Mint continue to use troy ounces as their official measurement in 2025.
Despite Australia’s metrication in the 1970s, the troy ounce endures for one main reason: global consistency. Precious metal prices on the world stage—whether you’re in Sydney, London, or New York—are quoted in troy ounces. This standardisation streamlines trading, investment, and storage, helping buyers and sellers avoid confusion or costly mistakes.
In 2025, with gold prices hitting new highs and silver demand surging among Australian investors, understanding troy ounces is more crucial than ever. The Australian Taxation Office (ATO) and the Perth Mint both reference troy ounces in their reporting and product specifications.
For Australians used to grams or kilograms, here’s a quick reference table to make conversions effortless:
| Troy Ounces (oz t) | Grams (g) | Kilograms (kg) | Avoirdupois Ounces (oz av) |
|---|---|---|---|
| 1 | 31.1035 | 0.03110 | 1.0971 |
| 5 | 155.5175 | 0.15552 | 5.4855 |
| 10 | 311.035 | 0.31104 | 10.971 |
| 32.1507 | 1,000 | 1 | 35.274 |
| 100 | 3,110.35 | 3.1104 | 109.71 |
Tip: If you’re working out the value of your bullion holdings or comparing prices, always check whether the figure is quoted in troy ounces or grams to avoid expensive mix-ups.
In today’s volatile markets, Australian investors are increasingly turning to physical gold and silver as a hedge against inflation and uncertainty. Understanding the troy ounce empowers you to:
For anyone serious about gold or silver, fluency in troy ounce measurements is a must in 2025’s fast-moving financial landscape.