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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.

By Rocco Clayfield, Founder & Director, GoldPaid Ltd · Published 18 September 2025 · updated 2 June 2026

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. 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.

Not sure how any of this applies to your own items? Send a photo on WhatsApp and ask. We answer honestly, there is no obligation, and nothing is posted until you decide. Or call 07944 014111, 8am to 9pm, 7 days a week.

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
1 tola11.6638gSouth Asian unit; exactly 3/8 of a troy ounce
1 baht (Thai)15.244gBar weight; ornaments are made to about 15.16g

What to do next

If you want to know what your own pieces are worth, start with a photo rather than a parcel. Send one on WhatsApp and we will tell you plainly what can and cannot be judged from an image. If you go ahead, the items are XRF-tested on arrival and you receive a written offer setting out the purity found, the weight and the rate used. Decline it and the tracked return costs you nothing. Accept it and payment is by Faster Payments within one working hour of acceptance.

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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.

Related guides

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Reference pages

Take it at your pace. Start with a WhatsApp photo and a question, ask anything about the XRF assay, the per-gram rate, the postal cover, or the return-if-you-decline route. Nothing is posted until you choose to post it, and the written offer is the first moment any decision actually counts.

GoldPaid is a registered UK business. Your prepaid Royal Mail Special Delivery label is addressed to us at Unit 217, Bristol Business Centre, 179 Whiteladies Road, Clifton, Bristol BS8 2AG, so you always know exactly where your parcel is going before you post it.

Send a photo on WhatsAppRequest a prepaid Royal Mail label

Ask for the label in that chat and we usually send it within 30 minutes during working hours, 8am to 9pm, 7 days a week. No printer? We send a QR code you show at the Post Office counter instead.

Ask first, post only when you are ready

Ask what your items are worth first

A photo and a question are the whole first step. We answer honestly, you decide whether to post, and you decide again, only after the written offer, whether to accept.

Send a photo on WhatsAppCall 07944 014111

Free prepaid label, usually sent within 30 minutes during working hours. Free tracked return if you decline. Faster Payments within one working hour of acceptance.

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