What is a troy ounce and how much does it weigh
The troy ounce, indicated by the symbol oz t, is the international reference unit for weighing gold, silver, and other precious metals.
One troy ounce corresponds to exactly 31.1035 grams. It is therefore different from the “standard” ounce (used in Anglo-Saxon countries for other goods), which weighs 28.35 grams. When you read that a one-ounce gold bar weighs 31.1 grams, you’re seeing a figure derived from an ancient measurement system called the troy system.
The name “troy” comes from the French city of Troyes, one of the most important trading centers in medieval Europe. As early as the 9th century, European merchants met there to trade coins, jewelry, and precious metals. To avoid weight discrepancies and ensure fair exchanges, they decided to adopt a common measure: thus, the troy ounce was born.
In the troy system, one pound equals about 373.24 grams, and the ounce represents one-twelfth of it, that is, 31.1035 grams. Since then, this unit has remained the benchmark for all physical gold transactions, both in international markets and among collectors and investors.
Today, the price of gold is expressed in U.S. dollars per troy ounce. This means that when we say “gold is trading at $2,400 per ounce,” we are referring to 31.1035 grams of pure gold (24 carats). Knowing how much an ounce of gold weighs is therefore essential for anyone investing in physical gold, whether buying bars or gold coins. For example, a 100-gram bar equals about 3.215 troy ounces, while a one-ounce coin, such as the famous Krugerrand or Maple Leaf, contains exactly 31.1035 grams of pure gold.
It’s fascinating to think that the troy ounce, born in medieval European fairs, is still today the basis of global gold trading. An ancient legacy that continues to ensure precision, transparency, and uniformity in the precious metals market.
Fun fact: the word “ounce” comes from the Latin uncia, meaning “one-twelfth part”!