How many carats are in one ounce?

One avoirdupois ounce equals approximately 141.75 carats. This comes from 1 ounce being about 28.3495 grams, divided by 0.2 grams per carat.

Should I not use troy ounces for gemstones?

Troy ounces (31.1035 g) are used for precious metals like gold and silver, not for gemstones. Gemstones use carats. The avoirdupois ounce (28.3495 g) is the common ounce used for everyday weighing. Using the wrong ounce type will give a roughly 10% error.

How much does a typical engagement ring weigh in ounces?

A complete engagement ring (metal band plus setting plus diamond) typically weighs 3 to 8 grams, or about 0.1 to 0.28 ounces. The diamond itself is usually only 5 to 15% of the total ring weight, with the gold or platinum making up the rest.

Carats to Ounces (ct to oz) Converter

1 ct = 0.0071 oz

1 Carat equals 0.0071 Ounces (1 ct = 0.0071 oz). Convert Carats to Ounces with formula, table, and examples.

One carat equals approximately 0.007055 ounces (avoirdupois). The avoirdupois ounce, at about 28.3495 grams, is roughly 141.75 times heavier than a single carat. This conversion is important for American consumers who think in ounces but encounter carat weights when shopping for jewelry, and for jewelers who need to report total shipment weights in ounces for domestic postal and freight calculations.

How to Convert Carats to Ounces

oz = ct × 0.0070547924

Multiply the value in Carats by 0.0070547924

Take your value in Carats
Multiply by 0.0070547924
Read the result in Ounces

Common Carats to Ounces Conversions

Carats (ct)	Ounces (oz)	Status
0.25 ct	0.0017637 oz
0.5 ct	0.0035274 oz
1 ct	0.00705479 oz
2 ct	0.01410958 oz
5 ct	0.03527396 oz
10 ct	0.07054792 oz
25 ct	0.17636981 oz
50 ct	0.35273962 oz
100 ct	0.70547924 oz
250 ct	1.7636981 oz
500 ct	3.52739619 oz
1,000 ct	7.05479239 oz
2,500 ct	17.63698097 oz
5,000 ct	35.27396195 oz
10,000 ct	70.5479239 oz

Good to Know About Carats to Ounces Conversion

The avoirdupois ounce (from Old French 'aveir de peis,' goods of weight) was designed for trade goods like wool, sugar, and grain. The gemstone world deliberately chose a different unit - the carat - because precious stones demanded finer granularity than ounces could provide. A 1-carat difference in diamond weight can mean thousands of dollars in value, making the ounce far too coarse for gemological commerce.

Carats to Ounces: What You Need to Know

A 1-ounce gold bar weighs about 141.75 carats, while a substantial 3-carat diamond weighs only about 0.021 ounces. The ounce is a practical unit for weighing finished jewelry (ring plus setting plus stone) since the metal setting typically outweighs the gemstone by a factor of 10 or more. A gold engagement ring with a 1-carat diamond might weigh 4 to 6 grams total, or about 0.14 to 0.21 ounces.

What is a 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.

Metric diamond weight gemstone grading pearl measurement

Learn more about Carat →

What is a 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.

Imperial Us-customary food packaging (US/UK) postal weight cooking (US)

Learn more about Ounce →

Going the other way? Use our Ounces to Carats converter.

Carats to Ounces FAQ

One avoirdupois ounce equals approximately 141.75 carats. This comes from 1 ounce being about 28.3495 grams, divided by 0.2 grams per carat.
Troy ounces (31.1035 g) are used for precious metals like gold and silver, not for gemstones. Gemstones use carats. The avoirdupois ounce (28.3495 g) is the common ounce used for everyday weighing. Using the wrong ounce type will give a roughly 10% error.
A complete engagement ring (metal band plus setting plus diamond) typically weighs 3 to 8 grams, or about 0.1 to 0.28 ounces. The diamond itself is usually only 5 to 15% of the total ring weight, with the gold or platinum making up the rest.

Non-Frequently Asked Questions About Carats to Ounces

Questions nobody should ask - but someone did.

The proverb says 'an ounce of prevention is worth a pound of cure.' In carats, an ounce is about 141.75 carats and a pound is about 2,268 carats. So apparently 141.75 carats of foresight saves you 2,268 carats of regret - a 16:1 return on investment. Ben Franklin would approve of this gemological reinterpretation.
A 1-carat diamond weighs 0.007 ounces, well under the 1-ounce first-class letter limit. You could technically mail it in a regular envelope, but postal insurance for a multi-thousand-dollar gem would cost more than the stamp. Registered mail with insurance is the standard method for shipping gems.
Gold trades at roughly 60 to 80 dollars per gram (as of the mid-2020s). A decent 1-carat diamond (0.2 grams) costs 4,000 to 10,000 dollars, or 20,000 to 50,000 dollars per gram. Gram for gram, diamonds are hundreds of times more expensive than gold, which is why jewelers weigh them to the hundredth of a carat.