Troy Weight Conversion Calculator

Convert between troy ounces, pennyweights, grams, and more. Essential for gold, silver, platinum, and precious metal trading, jewelry making, and collecting.

Important: A troy ounce is heavier than a standard ounce (31.1g vs 28.3g), but a troy pound is lighter than a standard pound (373g vs 454g). This confuses everyone!
1.09714 oz (avoir)
1 troy oz = 1.09714 standard oz
1 oz t → grams 100 g → oz t 1 oz t → dwt 20 dwt → oz t 1 oz t → grains 1 kg → oz t
31.1035 g
1 troy ounce
20 dwt
1 troy ounce
480 gr
1 troy ounce
1.09714 oz
1 troy ounce (standard)
What is Troy Weight?

The troy weight system dates back to the Middle Ages and originated in the trading city of Troyes, France. Today, it remains the global standard for quoting and trading gold, silver, platinum, and other precious metals.

Troy vs. Avoirdupois (Standard) Comparison

Unit Troy System Avoirdupois System (Standard)
Ounces per Pound 12 oz t per lb t 16 oz per lb
Ounce Weight 31.1035 g 28.3495 g
Pound Weight 373.24 g 453.59 g
Grains per Ounce 480 gr 437.5 gr
Memory Trick: "Troy ounces are Terrifically heavy, Troy pounds are Tiny."

Troy Units Explained

  • Troy Ounce (oz t): The most commonly used unit for precious metals. 1 troy oz = 31.1034768 grams exactly.
  • Pennyweight (dwt): Commonly used in jewelry and precious metal fabrication. 1 troy oz = 20 dwt.
  • Grain (gr): The smallest unit, common to troy, avoirdupois, and apothecary systems. 1 troy oz = 480 grains.
  • Troy Pound (lb t): Contains 12 troy ounces (rarely used today). 1 lb t = 373.24 g.

Why Troy Weight Matters

  • Precious Metals Trading: Gold, silver, platinum, and palladium prices are quoted per troy ounce. Accurate conversion ensures correct valuation.
  • Jewelry Manufacturing: Jewelers frequently convert between pennyweights, grams, and troy ounces during fabrication.
  • Investment & Collecting: Bullion bars, coins, and rounds are labeled in troy units. Converting to grams or standard ounces helps investors understand actual mass.
  • Avoiding Costly Errors: Mistaking troy ounces for standard ounces can lead to significant pricing mistakes when dealing with precious metals.

Common Conversion Formulas

  • Grams = Troy Ounces × 31.1034768
  • Pennyweights = Troy Ounces × 20
  • Grains = Troy Ounces × 480
  • Standard Ounces = Troy Ounces × 1.09714
  • Kilograms = Troy Ounces ÷ 32.1507466
  • Troy Ounces = Grams ÷ 31.1034768

Frequently Asked Questions

Yes. A troy ounce is approximately 31.1 grams, while a standard (avoirdupois) ounce is about 28.35 grams. So a troy ounce is about 10% heavier.

The troy system has been historically used in precious metal trading for centuries, originating in the French city of Troyes during the Middle Ages. It became the global standard and remains so today.

Exactly 31.1034768 grams in one troy ounce.

A pennyweight is 1/20 of a troy ounce, or 24 grains. It's commonly used in jewelry making and for small quantities of precious metals.