How many grams in a troy ounce (oz t to g)

One troy ounce is exactly 31.1034768 grams. A troy ounce is 480 grains, and the grain has been exactly 64.79891 milligrams since the 1959 international yard and pound agreement fixed the pound at 7,000 grains; 480 × 64.79891 mg is the whole derivation.

Worked through: 2 oz t x 31.1034768 = 62.207 g.

Going the other way, one gram is 0.0321507466 troy ounces.

For mental arithmetic: Multiply by 31.1, or by 30 and add 3.7%.

Two ounces share the name, and the troy one is heavier: 31.1035 g against the ordinary avoirdupois ounce's 28.3495 g, a difference of 9.7%. Gold, silver, platinum and palladium are priced per troy ounce everywhere, so a spot price per ounce is a price per 31.1 g, and a kitchen scale set to ounces reads a 1 oz t coin as 1.097 oz. The pound runs the other way: a troy pound is 12 troy ounces, 373.24 g, lighter than the 453.59 g pound of 16 ordinary ounces. Jewelers also use the pennyweight, a twentieth of a troy ounce, 1.555 g.

Precision is worth matching to the input. A measurement given as 0.1 oz t carries one or two significant figures, and reporting its conversion to six implies a precision the original never had.