Updated May 16, 2026

Carats to Troy Ounces Converter

Multiply carats by 0.00643015 to get troy ounces. 1 carat = 0.00643 troy ounces. It takes 155.517 carats to equal one troy ounce (31.1 grams).

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Common Conversions

Key Takeaways

  • 1 carat = 0.00643015 troy ounces.
  • 155.517 carats = 1 troy ounce.
  • Troy ounces are 9.7% heavier than regular ounces.
  • Both carats and troy ounces are used in the precious goods trade.
  • Multiply carats by 0.00643015 to convert.

How Do You Convert Carats to Troy Ounces?

Multiply carats by 0.00643015 to get troy ounces. The formula is: Troy Ounces = Carats x 0.00643015. This works because 1 carat = 0.2 grams and 1 troy ounce = 31.1035 grams, so 0.2 / 31.1035 = 0.00643015.

Sam Okafor appraises a vintage brooch containing a 25-carat amethyst set in gold. He needs the gemstone weight in troy ounces for the precious metals report: 25 x 0.00643015 = 0.16075 troy ounces. Combined with the 2.3 troy ounces of 14K gold in the setting, the total piece weighs 2.461 troy ounces.

Carats to Troy Ounces Reference Table

Carats Troy Ounces Also Equals
1 ct0.00643 oz t0.2 g
5 ct0.03215 oz t1.0 g
10 ct0.06430 oz t2.0 g
50 ct0.32151 oz t10.0 g
100 ct0.64302 oz t20.0 g
155.517 ct1.00000 oz t31.1 g
500 ct3.21508 oz t100.0 g

Practical Applications

Jewelry Appraisal and Insurance

Priya Patel helps a client document jewelry for an insurance claim. The collection includes 340 carats of various gemstones. Converting: 340 x 0.00643015 = 2.186 troy ounces. The insurer compares this alongside the gold content (8.5 troy ounces) to establish replacement values using current precious goods market rates.

Precious Metals and Gems Trading

Tom Brewer visits a coin and bullion shop that also deals in gemstones. A dealer offers a 75-carat parcel of garnets. Converting: 75 x 0.00643015 = 0.4823 troy ounces. Tom compares this to gold at roughly $2,000 per troy ounce — the garnet parcel weighs about half a troy ounce but costs a fraction of the same weight in gold.

Estate Settlement

Leah Nguyen helps her grandmother inventory heirloom jewelry for estate planning. The collection totals 186 carats of rubies, emeralds, and sapphires. Converting: 186 x 0.00643015 = 1.196 troy ounces. The estate attorney records both carat and troy ounce weights in the trust documentation, as financial institutions often track precious goods in troy ounces.


Related Calculators

Frequently Asked Questions

How many troy ounces is 1 carat?

One carat equals approximately 0.00643015 troy ounces. Since 1 carat = 0.2 grams and 1 troy ounce = 31.1035 grams, dividing 0.2 by 31.1035 gives this conversion factor.

How do I convert carats to troy ounces?

Multiply the carat value by 0.00643015. For example, 100 carats x 0.00643015 = 0.643015 troy ounces. You can also convert carats to grams (multiply by 0.2), then divide by 31.1035.

What is the difference between a troy ounce and a regular ounce?

A troy ounce is 31.1035 grams, while a regular (avoirdupois) ounce is 28.3495 grams. The troy ounce is about 9.7% heavier and is used exclusively for precious metals and gemstones.

Why are troy ounces used for precious metals?

Troy ounces date back to medieval Troyes, France, a major trading center. The troy system became standard for gold, silver, and platinum trading because it provided a consistent measure across international markets.

How many carats equal 1 troy ounce?

One troy ounce equals 155.517 carats. Since 1 troy ounce = 31.1035 grams and 1 carat = 0.2 grams, dividing 31.1035 by 0.2 gives 155.517 carats per troy ounce.