Beyond grams and troy ounces, bullion has a long tail of regional and historical weight units that still turn up in dealer quotes, family heirlooms and old paperwork. Knowing them stops you from being short-changed on an inheritance.
Grain (gr)
The smallest unit you’ll see for bullion.
- 1 grain = 0.06479891 grams.
- 1 troy ounce = 480 grains.
- 24 grains = 1 pennyweight (see below).
Originally based on the weight of a single grain of barley — quite literally where “grain” comes from. Used for very small amounts of precious metals (gold leaf, antique jewellery fittings) and still standard in the US for measuring gunpowder, bullets and some medicines.
A typical use case: a gold Sovereign weighs 123.27 grains of fine gold (= 7.32 g). You’ll occasionally see Sovereign weights quoted in grains in 19th-century paperwork.
The calculator accepts grains directly — pick “grains (gr)” from the unit dropdown.
Pennyweight (dwt)
The unit American jewellery scrap dealers still use.
- 1 pennyweight = 1.55517384 grams.
- 1 pennyweight = 24 grains.
- 20 pennyweights = 1 troy ounce.
The abbreviation dwt comes from the medieval Latin denarius weight — denarius being the Roman penny, which is also where the “d” in old British “£.s.d” (pounds, shillings, pence) comes from. A medieval English silver penny weighed about 1.5 grams.
US jewellers price scrap gold “per dwt” on the same logic UK dealers price per gram — it’s familiar to them. When you see a US dealer offer “$50/dwt for 14k gold scrap”, that converts to roughly £25/g for 14k gold in UK pricing terms — broadly competitive but always run the maths.
UK buyers selling scrap to a US dealer (or vice versa) should always reconcile to grams to avoid unit confusion.
Tola
The South Asian bullion unit.
- 1 tola = 11.6638 grams.
- 1 tola ≈ 0.375 troy ounces (handy approximate — sometimes called “10 grams plus a bit”).
Standard for gold trading in India, Pakistan, Bangladesh, Nepal and across the Gulf states. Indian Sovereign coins weigh exactly 1 tola. Indian gold biscuits — small flat bars sold informally for wedding and dowry purposes — typically come in 5g, 10g, 1 tola, 2 tola and 5 tola sizes.
UK families with Indian or Pakistani heritage often inherit gold in tola pieces. The calculator handles tola weights directly.
Baht
The Thai bullion unit.
- 1 baht = 15.244 grams (for 96.5% pure Thai gold — the standard purity).
- For purposes of pure-gold content: 1 baht = 14.71g fine gold.
Thai gold shops trade in baht-weight rings, chains and bars. The unit is unique because the Thai gold standard is 96.5% (not 99.9% like investment gold or 91.6% like a Sovereign) — so a “1 baht gold bar” contains 14.71g of pure gold inside a 15.24g gross piece.
If you’ve inherited or bought Thai gold, weigh it on a gram scale and multiply by 0.965 to get pure gold content. Then value at live spot.
Mace
The Chinese / Hong Kong unit.
- 1 mace = 3.7799 grams (the Hong Kong / international standard).
- 10 mace = 1 tael; 16 tael = 1 catty (used for tea and food, not gold).
You’ll see mace and tael units on Chow Sang Sang, Chow Tai Fook and other Hong Kong jewellery receipts. A typical 24k gold bracelet might be quoted as “2.5 tael” (~95g).
Putting it together — the conversion table
| Unit | Grams | Troy oz | Notes |
|---|---|---|---|
| 1 grain (gr) | 0.0648 | 0.00208 | Smallest practical bullion unit |
| 1 pennyweight (dwt) | 1.555 | 0.05 | US jewellery scrap |
| 1 gram (g) | 1 | 0.0322 | Universal standard |
| 1 mace | 3.78 | 0.1215 | Hong Kong / Chinese |
| 1 tola | 11.66 | 0.375 | Indian / South Asian |
| 1 baht (96.5% Au) | 15.24 | 0.490 | Thai gold |
| 1 troy ounce (oz t) | 31.10 | 1 | LBMA standard |
| 1 troy pound | 373.24 | 12 | Historical |
| 1 kilogram (kg) | 1,000 | 32.15 | Institutional |
Worked example — an inherited tola coin
You inherit a 10 tola gold biscuit, marked “999.9”.
- Total weight: 10 × 11.66g = 116.6 grams.
- Pure gold: 116.6 × 0.9999 = 116.6g fine gold.
- At a £85/g spot price: 116.6 × £85 = £9,911.
A UK bullion dealer will pay close to spot for a hallmarked .9999 piece from a recognised refiner. If the piece is unhallmarked, they’ll typically assay it first and pay 1–3% below spot.
Bullion value calculator — supports tola, baht, mace and all the above →
Why these units survive
In an age of grams, why are these old units still around?
- Heritage and tradition. Indian gold buying traces back centuries to the tola. Changing the unit would feel like changing the currency.
- Cultural transactions. Wedding gold, dowries, religious offerings — these markets price in tola or baht because that’s what every elderly relative understands.
- Trading-floor habits. US scrap jewellery dealers learned dwt from their parents who learned it from theirs. Change is slow.
- Government / Customs. Some countries still use traditional units for tax and customs purposes, even when domestic retail prices in grams.
If you’re trading internationally — selling gold to a US dealer, buying from a Hong Kong jeweller, inheriting from India — always convert to grams first as the neutral reference, then back to the target unit if needed. Mistakes here cost real money.