Troy Ounce Converter

A troy ounce is a unit of mass used almost exclusively for measuring precious metals — gold, silver, platinum, and palladium. One troy ounce equals exactly 31.1034768 grams, which makes it approximately 10% heavier than the avoirdupois ounce (28.3495 grams) used for everyday items like food and postal packages. The troy weight system originated in the French city of Troyes during the Middle Ages, where it was used in trade fairs to standardize the weighing of gold and silver coinage.

Today, nearly every major gold exchange — including the London Bullion Market Association (LBMA), COMEX in New York, and the Shanghai Gold Exchange — quotes prices per troy ounce. When you see a gold price quoted as $2,000, that means $2,000 per troy ounce, not per regular ounce. Understanding this distinction is essential for anyone buying or selling precious metals, as mistaking a regular ounce for a troy ounce can result in receiving nearly 10% less metal than expected.

The troy weight system includes smaller subdivisions: one troy ounce is divided into 20 pennyweights (dwt) or 480 grains. The grain is the smallest unit that is common to all three weight systems (troy, avoirdupois, and apothecaries), making it the universal bridge between them. This calculator handles all these conversions instantly, so you never need to do the arithmetic manually when evaluating precious metal purchases or selling your holdings.

The conversion factors used by this calculator are standardized internationally. The troy ounce is defined in terms of the gram, which itself is defined by the International System of Units (SI). All other conversions follow from this primary relationship.

To convert from any of these units back to troy ounces, simply divide by the same conversion factor. For example, to convert grams to troy ounces, divide the number of grams by 31.1035.

The troy ounce and the avoirdupois ounce are fundamentally different units from separate measurement systems, and confusing the two is one of the most costly mistakes you can make when buying or selling precious metals. A troy ounce weighs 31.1035 grams, while a regular (avoirdupois) ounce weighs only 28.3495 grams — a difference of 2.754 grams, or about 9.7%.

In practical terms, if you buy a silver bar labeled "100 ounces" and it was weighed using regular ounces, you would receive only 2,834.95 grams of silver instead of the 3,110.35 grams you would expect from 100 troy ounces. At a silver price of $25 per troy ounce, that confusion costs you over $240. For a gold bar at $2,000 per troy ounce, the same mistake could cost thousands of dollars.

The troy system uses only 12 ounces per troy pound, compared to 16 ounces in an avoirdupois pound. However, the troy ounce itself is heavier, so a troy pound (373.24 grams) is actually lighter than an avoirdupois pound (453.59 grams). This counterintuitive relationship is why the troy system is applied strictly to precious metals and never to the pound unit in commerce — gold traders always quote by the troy ounce, never by the troy pound.

The troy ounce converter is designed for quick, accurate conversions with a single input field. Here is how to use it effectively:

1. Enter the number of troy ounces in the input field at the top. The default value is 1 troy ounce, but you can enter any positive number — whether it is 0.5 for a small gold coin or 400 for a standard London Good Delivery gold bar.
2. View the primary result: The main result card instantly converts your troy ounces to grams with high precision, displayed prominently in the center of the page.
3. Check all unit conversions: Scroll down to see the equivalent value in grams, regular ounces, pennyweights, and grains, each displayed in separate result cards for quick reference.
4. Reference the quick comparison table: The quick reference section at the bottom shows common troy ounce landmarks — 1 troy ounce, 12 troy ounces (1 troy pound), and 32.15 troy ounces (1 kilogram) — with their equivalents side by side.

Use the regular ounce result if you need to compare precious metal weights to everyday objects. The grain conversion is particularly useful for reloading ammunition, as bullet weights are typically specified in grains using the same standard.

The troy ounce is the universal language of precious metals markets. Every gold price you see in the news, every silver futures contract on COMEX, and every platinum quote from a dealer is priced per troy ounce. The London Bullion Market, which sets the twice-daily gold price fix used as a global benchmark, specifies gold bars of approximately 400 troy ounces each — roughly 12.5 kilograms — as the standard delivery unit.

When you buy physical gold coins or bars, the weight stamped on them is almost always in troy ounces. Popular coins like the American Gold Eagle and Canadian Gold Maple Leaf are minted in denominations of 1 troy ounce, 1/2 ozt, 1/4 ozt, and 1/10 ozt. Silver coins follow the same convention. Even small gold jewelry pieces may be described in grains or pennyweight — a typical gold ring might weigh 2 to 5 dwt — making troy unit conversions essential for accurate valuation.

The kilogram (32.15 troy ounces) is increasingly used alongside the troy ounce in Asian precious metals markets, particularly in China and India. This calculator bridges the gap, letting you convert effortlessly between troy ounces and kilograms so you can compare prices quoted in different units across global markets. Whether you are a jeweler weighing a gold necklace in grams, a coin collector verifying mint specifications, or an investor calculating the value of your physical bullion, accurate troy ounce conversion is the foundation of every transaction.