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Gold knowledge

How gold is weighed: grams, troy ounces and pennyweights

Three units, one piece of metal. Knowing which is which avoids a common cause of confusion when comparing offers, and tells you what the buyer is actually doing.

Published 18 September 2025

How is gold weighed?In the trade gold is weighed in either grams or troy ounces. One troy ounce equals 31.1035 grams (not the same as a regular avoirdupois ounce). Pennyweights, an older unit equal to 1.555 grams, still appear in some pawnbroker and antique-jewellery contexts. The gram is the cleanest unit to compare offers on.

Grams: the default

A gram is a gram, the same in every context, and is the unit used by virtually all UK and European bullion and scrap pricing. When a buyer publishes a per-gram rate, that is exactly what they mean. GoldPaid prices and reports in grams, weighed to 0.01g precision.

Troy ounces: the bullion unit

Investment bullion (bars, sovereigns, krugerrands) is often quoted per troy ounce. One troy ounce equals 31.1035 grams. Importantly, it is not the same as a regular "avoirdupois" ounce used for groceries (28.3495g), confusing the two can cause meaningful errors. When converting a troy-ounce quote to a per-gram figure, divide by 31.1035.

Pennyweights: the old unit

A pennyweight (abbreviated "dwt") is one-twentieth of a troy ounce, or 1.555 grams. It is still used by some American pawnbrokers and in older jewellery-trade contexts. If you are comparing offers and one quotes "per dwt," translate to per-gram before comparing, a "high" per-dwt rate is much smaller in per-gram terms.

Quick conversions

FromTo gramsNotes
1 troy ounce31.1035gStandard bullion unit
1 avoirdupois ounce28.3495gNot used in bullion, do not confuse with troy
1 pennyweight (dwt)1.555g1/20 of a troy ounce
1 grain0.0648gOld jewellery unit; 24 grains = 1 dwt

Common questions

Is a troy ounce heavier than a normal ounce?

Yes. 31.1035g versus 28.3495g, roughly 10% heavier. Always check which "ounce" is being quoted in any precious-metal context; bullion always uses troy.

Should I worry about pennyweight quotes?

Mainly when comparing offers across buyers. A per-pennyweight figure looks higher than the equivalent per-gram figure simply because a pennyweight is larger than a gram. Translate to per-gram before comparing.

How precisely does GoldPaid weigh my items?

To 0.01 of a gram on calibrated scales, with mixed lots separated by carat before weighing.

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