What Is a Troy Ounce? Troy Ounce vs Regular Ounce, Explained

Picture a donut shop with two kinds of donut. The precious-metals donut is about 10% bigger than the ordinary one, but it comes in a box of 12 instead of 16. Weigh the boxes and the box of bigger donuts is lighter. That is the troy ounce and the troy pound, and it confuses nearly everyone the first time.

So, what is a troy ounce? A troy ounce is the unit used to weigh and price gold, silver, platinum and palladium. It is exactly 31.1034768 grams, about 9.7% heavier than the ordinary (avoirdupois) ounce of 28.35 grams used for food and mail. When you see a gold or silver price “per ounce,” it means per troy ounce. A troy pound, though, has only 12 troy ounces, so it is lighter than an ordinary pound: 373 grams against 454.

Troy ounce vs regular ounce

The troy ounce is heavier. The troy pound is lighter.

Weight in grams. Ounces and pounds are each drawn on their own scale.

The grain is the one unit both systems share: a troy ounce is 480 grains and an ordinary ounce is 437.5. Everything else follows from that.

How many grams are in a troy ounce?

Exactly 31.1034768 grams, because a grain is defined as exactly 0.06479891 grams and a troy ounce is 480 of them. For everyday purposes, 31.1 grams is close enough. To turn a price per ounce into a price per gram, divide by 31.1035: silver at $60 an ounce is $1.93 a gram, and gold at $4,000 an ounce is $128.60 a gram.

Why does my 1-ounce coin weigh more on a kitchen scale?

Because the kitchen scale is counting in ordinary ounces. A 1-troy-ounce Silver Eagle weighs 31.10 grams, which a kitchen scale set to ounces shows as about 1.10 oz. Switch the scale to grams and it should read close to 31.1. This is the single most common “is my coin fake?” question, and the answer is usually that the coin is fine and the scale is speaking a different dialect.

One more surprise: a 1-ounce Gold Eagle weighs 33.93 grams, not 31.10. It is 22-karat gold, so it holds one troy ounce of gold plus a little copper and silver to make it tougher. The “1 oz” on a coin means the precious metal inside, not the whole coin. For the real test, weigh in grams and compare with the mint’s figure; the coin checker does that for twenty coins, and the guide to testing silver covers the rest.

To convert any weight at once, the troy ounce converter shows grams, kilos, pounds, pennyweight and tola side by side.

A gram scale that reads to 0.01 g costs about as much as a pizza and settles most arguments before they start.

How many troy ounces are in a pound?

An ordinary pound is 14.58 troy ounces, not 16. This one matters when you buy or sell by weight. If someone offers “a pound of silver” weighed on a bathroom or kitchen scale, you are getting 14.58 ounces of the stuff prices are quoted in. Pay the 16-ounce price and you have overpaid by 1.42 ounces, which at $60 silver is $85. That is the donut box again: the label said 16, the box held 12 and a bit.

For bigger amounts: a 100-ounce silver bar weighs 3,110 grams, or about 6.86 ordinary pounds, and a kilo bar holds 32.15 troy ounces. The junk silver guide uses the same arithmetic for bags of old coins, where $1,000 in face value weighs about 55 pounds.

Why are gold and silver weighed in troy ounces?

Habit, mostly, and a very old one. The system is generally thought to be named for Troyes, a market town in France where English merchants traded in the Middle Ages, though historians have other theories too. Troy weight became the standard for precious metals in England, and the United States followed: Congress made the troy ounce the official weight for American coinage on May 19, 1828.

Most other troy units have since been retired. In Britain the Weights and Measures Act 1985 kept only the troy ounce, and only for precious metals. Markets around the world, metric countries included, still quote gold and silver per troy ounce, which is why a Canadian Maple Leaf, an Austrian Philharmonic and an American Eagle all say “1 oz” and mean 31.1 grams.

Is a troy ounce the same as a fluid ounce?

No. A fluid ounce measures volume, not weight; it is how much liquid fits in a space. A troy ounce of pure gold, as a Gold Buffalo, is a coin 32.7 mm across; a troy ounce of pure silver, as a Silver Eagle, is 40.6 mm across and thicker, because silver is a little over half as dense. Same weight, different size. The money weight calculator shows how big a million dollars in each metal would be.

The fair objection

It would be simpler if the metals trade switched to grams, and parts of it have. Many Asian markets price gold per gram, refiners make bars in grams and kilos, and the troy ounce survives mostly because everyone already uses it. That’s a fair complaint about the system. It just doesn’t change the price of anything: the metal weighs what it weighs, and the units are only the box it comes in.

Back to the donut shop

Remember the two kinds of donut and the two kinds of box, and the troy system stops being strange. The troy ounce is the bigger donut, the troy pound is the smaller box, and every price you will see for gold or silver is per donut.

Sources

• The troy ounce (480 grains, 31.1034768 g), troy pound, pennyweight and grain; the Troyes origin and its alternative; the US Act of May 19, 1828; the troy ounce under the UK Weights and Measures Act 1985: Wikipedia, Troy weight.
• The ordinary (avoirdupois) ounce and pound, 28.349523125 g and 453.59237 g: Wikipedia, Ounce.
• Coin weights and diameters (Silver Eagle 31.103 g and 40.6 mm, Gold Eagle 33.931 g, Gold Buffalo 32.7 mm): the specification table on this site’s Is My Coin Fake? checker, with its sources.

Every other figure on this page is worked from those definitions. Sources read October 17, 2026.

Questions people actually ask

What is a troy ounce?

A troy ounce is the unit used to weigh and price gold, silver, platinum and palladium. It is exactly 31.1034768 grams, about 9.7% heavier than the ordinary ounce of 28.35 grams used for food and mail.

How many grams are in a troy ounce?

31.1034768 grams exactly, because a troy ounce is 480 grains and a grain is defined as 0.06479891 grams. For everyday use, 31.1 grams is close enough.

Is a troy ounce heavier than a regular ounce?

Yes. A troy ounce is 31.10 grams and a regular (avoirdupois) ounce is 28.35 grams, so the troy ounce is about 9.7% heavier. One troy ounce is 1.097 regular ounces.

How many troy ounces are in a pound?

A regular pound is 14.58 troy ounces. A troy pound is 12 troy ounces, or 373 grams, which makes it lighter than a regular pound of 454 grams.

How many troy ounces are in a kilogram?

32.15 troy ounces. A metric ton is 32,150.7 troy ounces.

Is the gold price per troy ounce?

Yes. When gold, silver, platinum or palladium is quoted per ounce, it means per troy ounce, even in countries that otherwise use metric units.

Why does my 1 oz silver coin weigh 1.1 oz on my scale?

Because a kitchen or postal scale measures regular ounces. A 1-troy-ounce coin weighs 31.10 grams, which is about 1.10 regular ounces. Switch the scale to grams and it should read close to 31.1.

Why does a 1 oz Gold Eagle weigh more than 31.1 grams?

The Gold Eagle is 22-karat gold. It contains one troy ounce of gold plus a little copper and silver, so the whole coin weighs 33.93 grams. The 1 oz on a coin refers to the precious metal inside.

Why is it called a troy ounce?

The name is generally thought to come from Troyes, a market town in France where English merchants traded in the Middle Ages, though there are other theories. Troy weight became the standard for precious metals in England and later in the United States.

How do I convert a price per ounce to a price per gram?

Divide by 31.1035. Silver at $60 a troy ounce is $1.93 a gram, and gold at $4,000 a troy ounce is $128.60 a gram.