Difference Between Ounce and Troy Ounce

Ounce vs Troy Ounce

Ounce is a unit of measurement of weight and is used in many countries. Roughly equal to 28 grams, ounce is used in many systems but two more popular systems are avoirdupois ounce and troy ounce. Avoirdupois ounce is simply known as ounce and used in all parts of the world but it is troy ounce that holds significance when it comes to measurement of weights of precious metals. Let us see the difference between ounce and troy ounce as any mistake on the part of a buyer can cost him in hundreds of dollars when it comes to gold and silver.

For everyday weighing, it is avoirdupois ounce that is commonly used. If you weigh yourself on a scale, you get your weight in pounds and ounces that are avoirdupois ounces and avoirdupois pounds.

1 avoirdupois ounce =437.5 grains or 28.35 grams

1 avoirdupois pound contains 16 ounces, which makes it 453.6 grams.

Troy ounce is heavier than the ounce used in a grocery store. It is used in precious metals. So when you buy an ounce of gold or silver, you are getting a troy ounce and not ordinary, everyday ounce. It weighs 10% more than common ounce and has 31.1 grams in comparison to ounce that has 28.35 grams.

It is believed that troy ounce is older than an ounce and was used in Troyes France in the Middle Ages. We know that a troy ounce is heavier than an ounce. But since a troy pound contains 12 troy ounces and an avoirdupois pound contains 16 ounces, a troy pound is lighter than an ordinary pound.

So we know now that a troy ounce weighs 31.1 gm whereas an avoirdupois ounce weighs 28.35gm. The formula to convert grocery ounce into toy ounce is as follows.

Regular ounceX0.912 = troy ounces.

In brief:

• Ounce is a unit of measurement of weights while a troy ounce is especially used for the measurement of precious metals

• Troy ounce is heavier than ordinary ounce

• While ordinary ounce contains 28.35 gm, a troy ounce contains 31.1 gm