# Carats to Troy Ounces (ct to oz t) Source: https://www.unitconvertercalculator.com/weight/carats-to-troy-ounces/ **1 ct = 0.0064301493137256 oz t** One carat equals approximately 0.006430 troy ounces. The troy ounce (31.1035 grams) is the standard weight unit for precious metals like gold, silver, and platinum. Since a carat (0.2 grams) is roughly 1/155 of a troy ounce, this conversion is essential in the jewelry industry where gemstone weights in carats must be combined with metal weights in troy ounces for pricing and documentation. ## Formula Apply the conversion factor ## Conversion Table | Carats (ct) | Troy Ounces (oz t) | |---|---| | 0.25 ct | 0.0016075373284314 oz t | | 0.5 ct | 0.0032150746568628 oz t | | 1 ct | 0.0064301493137256 oz t | | 2 ct | 0.012860298627451 oz t | | 5 ct | 0.032150746568628 oz t | | 10 ct | 0.064301493137256 oz t | | 25 ct | 0.16075373284314 oz t | | 50 ct | 0.32150746568628 oz t | | 100 ct | 0.64301493137256 oz t | | 155.517 ct | 0.99999753082266 oz t | | 250 ct | 1.6075373284314 oz t | | 500 ct | 3.2150746568628 oz t | | 1000 ct | 6.4301493137256 oz t | | 5000 ct | 32.150746568628 oz t | ## Units ### Carat (ct) A carat is a unit of mass equal to exactly 200 milligrams (0.2 grams), used for measuring gemstones and pearls. Adopted internationally in 1907 by the Fourth General Conference on Weights and Measures. ### 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 A jeweler crafting a gold ring with a 1-carat diamond works with two different weight systems simultaneously: the diamond is 0.2 grams (1 carat) while the gold might be 5 grams (0.161 troy ounces). Gold is priced per troy ounce on global markets, diamonds per carat. Understanding the relationship between the two units helps jewelers price finished pieces and calculate material costs accurately. ## Good to Know The troy ounce has been the international gold standard since the Middle Ages. When financial news reports gold at '$2,000 an ounce,' the ounce is always troy. This creates an ongoing source of confusion: a troy ounce of gold sounds the same as a regular ounce but weighs 9.7% more. The coexistence of troy ounces (for metals) and carats (for gems) in the same jewelry shop is one of commerce's most enduring measurement dualities. ## FAQ ### How many carats are in one troy ounce? One troy ounce (31.1035 grams) equals approximately 155.517 carats. This comes from dividing 31.1035 grams by 0.2 grams per carat. ### How does a troy ounce differ from a regular ounce? A troy ounce is 31.1035 grams, about 9.7% heavier than the common avoirdupois ounce (28.3495 grams). Troy ounces are used exclusively for precious metals. When gold prices are quoted 'per ounce,' it always means per troy ounce. ### Why do precious metals use troy ounces while gemstones use carats? Historical tradition. Troy weight evolved from medieval European bullion trading (possibly named after Troyes, France). The carat evolved from gemstone trading using carob seeds as counterweights. Each industry kept its own units because switching would disrupt centuries of pricing conventions. ## Non-Frequently Asked Questions ### If gold costs 2,000 dollars per troy ounce, what would a troy ounce of diamonds cost? A troy ounce is 155.5 carats. At mid-range diamond prices (5,000 to 10,000 dollars per carat for decent quality), a troy ounce of diamonds would cost roughly 780,000 to 1.5 million dollars. Gold at 2,000 dollars per ounce is practically a bargain in comparison. ### Was the city of Troy famous for its ounces? The troy weight system is probably named after Troyes, a medieval French market city famous for its trade fairs - not the ancient city of Troy from Homer's Iliad. Priam's treasure was weighed in something, but it was not troy ounces. The naming coincidence has confused students of both history and measurement for centuries. ### If I wear a gold necklace with diamonds, how many weight systems am I wearing? At least two. The gold is priced in troy ounces, the diamonds in carats. If the clasp is stainless steel, add avoirdupois ounces. And if you bought it by the gram, that is the metric system too. A single piece of jewelry can simultaneously exist in four weight systems. 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