# Ounces to Troy Ounces (oz to oz t)

Source: https://www.unitconvertercalculator.com/weight/ounces-to-troy-ounces/

**1 oz = 0.91145833333333 oz t**

One avoirdupois ounce equals approximately 0.9115 troy ounces. Despite sharing the name 'ounce,' these two units differ by about 10 percent: an avoirdupois ounce is 28.3495 grams while a troy ounce is 31.1035 grams. The troy ounce is heavier and is used exclusively for precious metals, while the avoirdupois ounce measures everything else.

## Formula

Apply the conversion factor

## Conversion Table

| Ounces (oz) | Troy Ounces (oz t) |
|---|---|
| 1 oz | 0.91145833333333 oz t |
| 2 oz | 1.8229166666667 oz t |
| 5 oz | 4.5572916666667 oz t |
| 10 oz | 9.1145833333333 oz t |
| 25 oz | 22.786458333333 oz t |
| 50 oz | 45.572916666667 oz t |
| 100 oz | 91.145833333333 oz t |
| 500 oz | 455.72916666667 oz t |
| 1000 oz | 911.45833333333 oz t |

## Units

### Ounce (oz)

An imperial and US customary unit of mass equal to approximately 28.35 grams. Commonly used in the US and UK for food and postal weight.

### Troy Ounce (oz t)

A troy ounce is a unit of mass used for precious metals such as gold, silver, and platinum. It equals exactly 31.1034768 grams, about 10% heavier than the common avoirdupois ounce.

## Background

When gold prices are quoted at '$2,000 per ounce,' that is per troy ounce, not the common ounce used at the grocery store. A gold investor buying what they think is one ounce of gold receives 31.1 grams, not 28.35 grams. This distinction matters critically in precious metals trading, where the 2.75-gram difference per ounce adds up to significant value across large transactions.

## Good to Know

The troy ounce's name comes from Troyes, a city in the Champagne region of France that hosted major medieval trade fairs where merchants from across Europe converged. The weight standards used at these fairs became the basis for precious metals trading throughout Europe, and the troy system's survival into the 21st century makes it one of the longest-lived commercial standards in Western civilization.

## FAQ

### What is the difference between an avoirdupois ounce and a troy ounce?

An avoirdupois ounce weighs about 28.35 grams, while a troy ounce weighs about 31.10 grams. The troy ounce is approximately 9.7 percent heavier. Avoirdupois ounces measure everyday goods; troy ounces measure gold, silver, platinum, and palladium.

### Why do precious metals use a different ounce?

The troy system predates the avoirdupois system and was established specifically for precious metals trading, originating from the French town of Troyes, a medieval trade fair center. When the avoirdupois system became standard for general commerce, precious metals retained the older troy system to maintain pricing consistency across centuries of trading records.

### How do I convert avoirdupois ounces to troy ounces?

Multiply avoirdupois ounces by 0.9115 to get troy ounces. Alternatively, multiply by 28.3495 to convert to grams first, then divide by 31.1035 to get troy ounces. For rough mental math, subtract about 10 percent from the avoirdupois figure.

## Non-Frequently Asked Questions

### If a troy ounce is heavier, do I get ripped off buying gold by the ounce?

No, you actually get more gold per 'ounce' than you would if gold were sold in avoirdupois ounces. The troy ounce gives you 31.1 grams versus 28.35 grams, so the troy system is slightly generous by avoirdupois standards. Of course, the price per troy ounce already reflects this, so no one is getting a secret deal.

### Are there two competing ounce gangs fighting for territory?

In a manner of speaking. The avoirdupois ounce controls the general merchandise territory (food, packages, people), while the troy ounce holds exclusive rights to the precious metals district (gold, silver, platinum). They have coexisted in this uneasy arrangement since the Middle Ages without either managing to eliminate the other.

### If I accidentally weighed my gold in avoirdupois ounces, how much money would I lose?

You would undercount your gold by about 9.7 percent. On a 10-ounce gold bar worth roughly $20,000 at current prices, that mistake would cost you about $1,940. This is why jewelers, refiners, and coin dealers are extremely particular about which ounce they mean, and why 'just an ounce' is never a safe assumption in the gold business.

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## See Also

- [Troy Ounces to Ounces](https://www.unitconvertercalculator.com/weight/troy-ounces-to-ounces/)