One troy ounce equals exactly 31.1034768 grams. The everyday avoirdupois ounce is 28.349523125 grams. Substituting one for the other understates the weight of a troy ounce by about 8.85%.
The conversion that keeps the price consistent
To convert a price per troy ounce into a price per gram, divide by 31.1034768. To convert that price per gram into a kilogram price, multiply by 1,000. Keep full precision during the calculation and round the displayed money amount at the end.
For a deliberately hypothetical price of USD 3,000 per troy ounce, the gram equivalent is approximately USD 96.45. A 10-gram item made entirely of fine gold would have a reference metal value of approximately USD 964.52. This example is arithmetic, not a current market quotation.
Gross weight and fine weight
A 10-gram jewellery item is not necessarily 10 grams of gold. Gross weight includes the alloy; fine weight is the amount of the specified precious metal. Stones, springs and non-gold fittings can also affect a jewellery estimate. Multiply the eligible metal weight by its purity fraction before applying a fine-metal price.
Other useful units
A metric tonne is 1,000 kilograms. An avoirdupois pound is 453.59237 grams. Our metal weight converter treats a tola as 11.6638038 grams; regional or product conventions should still be confirmed with the seller. A troy pound is not the everyday pound and is not used by our pound selector.
Use the calculator safely
Select the physical weight unit first, enter a positive weight, then choose the correct purity. The metal value calculator displays its reference price and basis. A conversion does not include dealer premiums or establish the authenticity of an item.
Test yourself. Check what you learned with the units and conversions challenge quiz: 5 quick questions, each with a short explanation.
Sources & further reading
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