Gold: Penny Weight Vs. Gram Weight

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When weighing gold and other precious metals, you must use a different method or weights, called troy ounces. These are measured in units of pennyweights or gold grams.

1 Penny Weight

There are 20 pennyweights in a troy ounce, commonly abbreviated as DWT. The pennyweight was the actual weight of a medieval British silver penny and has remained the traditional method of weight for gold and other precious metals.

2 Gold Grams

There are 31.1 gold grams in a troy ounce.

3 Food and Postage Grams

In common food and postage weights, there are 28 g per ounce.

4 Troy Ounce

A troy ounce weighs about 10 percent more than 1 oz. of food and is used for weighing precious metals. It is called a troy ounce after the system of weights used in Troye, France, in medieval times.

5 Conversions

To convert gold grams to pennyweight, multiply by .64. To convert pennyweight to gold grams, multiply by 1.555.

Margaret Denett has been writing professionally for online publications since 2007. She writes for Answerbag and eHow, covering education, family issues, being thrifty as well as health, medical and science areas. She holds a Bachelor of Science in education from the University of Oregon, where she is pursuing a master's degree in education.