How many grains are in one troy ounce?

Exactly 480 grains. This is a defining constant of the troy weight system. No rounding or approximation is involved.

How do I convert troy ounces to grains?

Multiply troy ounces by 480. For example, 5 troy ounces equals exactly 2,400 grains.

Why is the grain shared between troy and avoirdupois systems?

The grain was the original common reference point for all English weight systems, defined as the weight of a single grain of barley. Both the troy and avoirdupois systems built their larger units from this shared foundation, though they diverged in their ounce and pound definitions.

Troy Ounces to Grains (oz t to gr) Converter

1 oz t = 480 gr

1 Troy Ounce equals 480 Grains (1 oz t = 480 gr). Convert Troy Ounces to Grains with formula, table, and examples.

One troy ounce equals exactly 480 grains. This is a defining relationship of the troy system: the troy ounce is 480 grains, the pennyweight is 24 grains, and the troy pound is 5,760 grains. The grain is the one unit shared between the troy and avoirdupois systems, making it the Rosetta Stone of English weight measurement.

How to Convert Troy Ounces to Grains

gr = oz t × 480

Multiply the value in Troy Ounces by 480

Take your value in Troy Ounces
Multiply by 480
Read the result in Grains

Common Troy Ounces to Grains Conversions

Troy Ounces (oz t)	Grains (gr)	Status
0.1 oz t	48 gr
0.25 oz t	120 gr
0.5 oz t	240 gr
1 oz t	480 gr
2 oz t	960 gr
5 oz t	2,400 gr
10 oz t	4,800 gr
25 oz t	12,000 gr
50 oz t	24,000 gr
100 oz t	48,000 gr
250 oz t	120,000 gr
500 oz t	240,000 gr
1,000 oz t	480,000 gr

Good to Know About Troy Ounces to Grains Conversion

The 480-grain troy ounce is the foundational relationship of precious metals measurement worldwide. Every gold price, every silver quote, every platinum contract ultimately references the troy ounce and its 480-grain definition. The choice of 480 grains, with its extraordinary divisibility, was one of the most mathematically astute decisions in the history of commerce.

Troy Ounces to Grains: What You Need to Know

Gold assayers and precious metals refiners use both troy ounces and grains in their work. Assay results may report gold content in grains per sample, which must be converted to troy ounces for commercial pricing. A gold bar assayed at 9,600 grains contains exactly 20 troy ounces of gold.

What is a 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.

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Learn more about Troy Ounce →

What is a Grain? gr

A grain is a unit of mass equal to exactly 64.79891 milligrams. It is the same in the avoirdupois, troy, and apothecaries' systems, derived from the 1959 international agreement defining the pound as exactly 0.45359237 kilograms.

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Learn more about Grain →

Going the other way? Use our Grains to Troy Ounces converter.

Troy Ounces to Grains FAQ

Exactly 480 grains. This is a defining constant of the troy weight system. No rounding or approximation is involved.
Multiply troy ounces by 480. For example, 5 troy ounces equals exactly 2,400 grains.
The grain was the original common reference point for all English weight systems, defined as the weight of a single grain of barley. Both the troy and avoirdupois systems built their larger units from this shared foundation, though they diverged in their ounce and pound definitions.

Non-Frequently Asked Questions About Troy Ounces to Grains

Questions nobody should ask - but someone did.

480 grains is exactly one troy ounce, worth about $2,200 at current prices. For a recreational gold panner, finding an entire troy ounce in a single trip would be exceptional, roughly a month's yield for most amateur operations. For a professional mine, one troy ounce is a few minutes of production.
Remarkably so. 480 = 2⁵ x 3 x 5, giving it factors of 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 20, 24, 30, 32, 40, 48, 60, 80, 96, 120, 160, 240, and 480. This extraordinary divisibility was deliberately chosen to facilitate the complex subdivision of precious metals by weight in pre-calculator commerce.
Modern barley grains weigh roughly 40 to 65 milligrams each, meaning 480 barley grains would weigh about 19 to 31 grams. A troy ounce is 31.1 grams, so the upper end of the barley range is remarkably close. The historical grain weight was standardized long ago at 64.799 milligrams, but the original barley reference was surprisingly accurate.