Jewelry weight units: grams, troy ounces, pennyweights and more
Enter a weight in any unit and see it in the other five at once. Handy for reading quotes in ounces, supplier invoices in pennyweights or a stone's weight in carats.
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Unit converter
Enter a weight and see it in every unit at once.
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- Grams31.103 gThe everyday unit in Mexico, Latin America and Europe: pieces are weighed, labor is charged and gold is bought by the gram.
- Troy ounces1.0000 oz tThe unit of international gold, silver and platinum quotes, and of investment bars.
- Pennyweights20.000 dwtWhat US workshops and suppliers use for metal, findings and casting.
- Grains480.0 grFor very small weights: solder, antique pearls and fine metal. 24 grains make a pennyweight.
- Carats (ct)155.517 ctThe weight of gemstones: diamonds, emeralds, rubies. Not the karat of gold, which measures purity.
- Tolas2.6667 tolaThe traditional gold measure in India, Pakistan, Nepal and the Persian Gulf.
How to convert weight units
- 1.Enter the weight you have.
- 2.Choose its unit: grams, troy ounces, pennyweights, grains, carats or tolas.
- 3.Read the same weight in the other five units.
- 4.Under each result there is a note on when that unit is used.
The 6 weight units of jewelry
Precious metals are not weighed in ordinary ounces. The troy ounce weighs 31.1035 g, more than the 28.35 g kitchen ounce, and it is the unit gold, silver and platinum are quoted in worldwide.
US workshops and suppliers use the pennyweight (dwt): one twentieth of a troy ounce, 1.5552 g. The grain, 0.0648 g, is for very small weights; 24 grains make a pennyweight.
The carat (ct) is a 0.2 g unit of weight for gemstones. It is not the karat of gold, which measures purity, not weight.
The tola, 11.66 g, is the traditional gold unit in India, Pakistan, Nepal and the Gulf states, where 10-tola bars are still sold.
Frequently asked questions
How many grams are in a troy ounce?
Exactly 31.1034768 g. It is the unit international gold is quoted in: the price per gram is the price per troy ounce divided by 31.1035.
What is a pennyweight (dwt)?
One twentieth of a troy ounce: 1.5552 g. US jewelers and suppliers use it for metal and findings; 20 dwt make a troy ounce.
Is a diamond carat the same as a gold karat?
No. The gemstone carat (ct) is weight: 0.2 g. The gold karat (K) is purity: how many of 24 parts are gold. A 1 ct diamond weighs 0.2 g; a 14K ring is 58.3 % gold.
How many grams is a tola?
11.6638 g, which is 180 grains or 0.375 troy ounces. It is the traditional unit for gold in South Asia and the Persian Gulf.
Why isn't gold weighed in ordinary ounces?
Tradition: the troy system comes from the fairs of Troyes, in France, where precious metals were weighed in the Middle Ages, and the gold market never left it. The ordinary (avoirdupois) ounce weighs 28.35 g.