When comparing the weight of 1 oz (ounce) versus 1 troy ounce, it is important to understand the difference between these two units of measurement. An ounce is a unit of weight commonly used in the United States and the Imperial system of measurement. A troy ounce is a different unit of weight primarily used to measure precious metals such as gold, silver, platinum and palladium. The main differences between the two are:
What is an Ounce?
An ounce (abbreviated as oz) is a unit of weight equal to 28.35 grams. It is widely used in the United States and other countries that follow the Imperial or United States customary systems of measurement. Under this system, one ounce is defined as 1/16 of a pound. Ounces are commonly used to measure the weight of a variety of everyday items such as food, liquids, and small objects. Some examples of things measured in ounces include:
- 1 oz of flour
- 1 oz of cheese
- 1 oz of nuts
- 1 oz of soda or juice
- 1 oz of sugar
- 1 oz of chocolate
In cooking and baking recipes, ingredients are often listed with their weights in ounces. Ounces are also used by the United States Postal Service to calculate postage rates based on the weight of letters and packages. In addition, ounces are a standard unit of weight used by fishermen to weigh their catch.
What is a Troy Ounce?
A troy ounce (abbreviated as ozt) is a unit of weight traditionally used for precious metals. It equals 31.1034768 grams, which makes it heavier than a regular ounce. The main difference is that a troy ounce is 20% heavier than a regular ounce since it contains 480 grains compared to the 437.5 grains in a standard ounce. This distinction was created in the Middle Ages to be used specifically for weighing gold, silver, platinum and other high-value metals.
The term “troy” comes from the French city of Troyes, which was an important European trade and finance center in the Middle Ages. Merchants and bankers in Troyes needed consistent, reliable weights to weigh precious metals for trade and currency. The troy system helped standardize the weights used for this purpose. Although troy ounces are primarily used only for bullion and precious metals today, at one time they were also used for everyday items like coins, spices, and medicines.
Some examples of items measured in troy ounces today include:
- 1 ozt of gold
- 1 ozt of silver
- 1 ozt of platinum
- 1 ozt of palladium
Precious metals like these are still traded and valued by their weights in troy ounces around the world. For this reason, troy ounces remain the standard unit of measurement for these commodities.
Ounce Comparison
To summarize the key differences:
| Unit | Abbreviation | Grams | Grains | Used for |
|---|---|---|---|---|
| Ounce | oz | 28.35g | 437.5 | Everyday goods |
| Troy Ounce | ozt | 31.10g | 480 | Precious metals |
As the table illustrates, the primary differences are:
- A troy ounce weighs 31.10 grams while a regular ounce is 28.35 grams.
- A troy ounce contains 480 grains compared to 437.5 grains in a regular ounce.
- Troy ounces are used for weighing precious metals while regular ounces are used for everyday goods.
So in summary, a troy ounce is heavier than a standard ounce because it has more grams and grains. The precise weights are:
- 1 oz = 28.35 grams
- 1 troy oz = 31.10 grams
Why the Difference?
The main reason for having two distinct ounce measurements is the need for consistency and precision when weighing valuable metals. Precious metals have historically been used as currency and required accurate weighing systems. The troy system was developed specifically for this purpose during the Middle Ages in Europe. Having a heavier troy ounce helped ensure reliable valuations when exchanging gold and silver bullion between banks and traders.
Over time, the troy system became the standard for weighing all precious metals around the world. It continues to be used today to keep valuations and pricing consistent in global precious metal markets. Although regular ounces are perfectly suitable for everyday goods, troy ounces provide the precision necessary for large financial transactions involving metals like gold and silver.
Which is Heavier?
To answer the original question directly: a troy ounce is heavier than a regular ounce. A single troy ounce weighs 31.1034768 grams. A single regular ounce weighs 28.349523125 grams. So a troy ounce is about 10% heavier than a standard ounce.
This weight difference matters significantly for measuring and pricing precious metals. Even small variations in weight for gold or silver can mean price changes of hundreds or thousands of dollars, especially on larger bullion trades. Using troy ounces helps eliminate these discrepancies.
Pricing Precious Metals
When checking precious metal prices online or in a financial newspaper, the troy ounce is always used rather than the avoirdupois ounce. For example:
- The price of gold may be listed as “$1,250 per oz t”
- Silver may be listed as “$17.15 per oz t”
- Platinum may be listed as “$950 per oz t”
You will never see precious metals priced per regular avoirdupois ounce. The troy system provides the level of precision required when dealing with the high value and small weights of precious metals trading.
Converting Between Ounce Types
While regular ounces are perfectly fine for everyday use, you may sometimes need to convert between troy and avoirdupois ounces. Here are the conversion formulas:
- 1 troy ounce = 1.09714 avoirdupois ounces
- 1 avoirdupois ounce = 0.911458 troy ounces
So if you needed to convert 2 troy ounces to avoirdupois ounces, the calculation would be:
2 x 1.09714 = 2.19428 avoirdupois ounces
Converting in the other direction, if you had 3 avoirdupois ounces, the calculation would be:
3 x 0.911458 = 2.73437 troy ounces
Ounce Conversions in Cooking
In cooking recipes that use regular ounces, you can safely substitute troy ounces since the difference is less than 10%. The resulting change to the ingredient weights will be negligible. However, you should never substitute regular ounces for troy ounces when specifically measuring precious metals for pricing or valuation purposes. Those transactions require the troy ounce’s precision.
Summary
In summary:
- A troy ounce is heavier than a regular avoirdupois ounce.
- Troy ounces weigh 31.10 grams vs. 28.35 grams for a regular ounce.
- The troy system was created to reliably weigh gold, silver and other precious metals.
- Troy ounces are still used today when pricing bullion such as gold and silver.
- For most everyday uses, the avoirdupois ounce is perfectly sufficient.
- You can convert between the two using simple multiplication.
So while both units are called “ounces”, the troy ounce is specially designed for precious metals and is approximately 10% heavier than the ounces used for everyday goods. Understanding this difference allows you to compare the weights accurately and determine which type of ounce is appropriate for a given use.
