Pennyweight
Also: dwt, DWT, Penny Weight
The pennyweight (dwt) is a unit of weight in the troy system equal to 1/20 of a troy ounce, used above all in the Anglo-American jewellery and goldsmithing trade.
The pennyweight (abbreviation: dwt) is a unit of weight from the troy weight system, which has been used since the Middle Ages for weighing precious metals and coins. The name derives from the English penny: in medieval England a silver penny coin weighed exactly one pennyweight. The abbreviation dwt goes back to the Latin denarius weight – the denarius was the Roman forerunner of the penny.
Conversions at a glance
| Unit | Value in dwt |
|---|---|
| 1 pennyweight (dwt) | 1 dwt |
| 1 troy ounce (ozt) | 20 dwt |
| 1 troy pound | 240 dwt |
| 1 grain | 1/24 dwt |
In metric units:
1 dwt = 24 grains = 1/20 troy ounce ≈ 1.55517 grams
For comparison: the avoirdupois ounce (the everyday commercial ounce) corresponds to about 18.23 dwt – so it is lighter than a troy ounce (20 dwt).
Use in practice and trade
In continental Europe the pennyweight plays hardly any role; there grams and the troy ounce dominate as standard units. It is different in the Anglo-American market: goldsmiths, jewellers and pawnshops in the USA, Canada and Australia regularly quote scrap-gold buying prices in dwt. Anyone selling broken gold or jewellery there will therefore frequently encounter the pennyweight in offers and price lists.
Typical use cases:
- Valuing scrap gold and jewellery on purchase
- Weight specifications in US coin and auction catalogues
- Dental-gold valuation (particularly in the North American market)
The spot price per dwt is calculated simply:
Price/dwt = spot price (USD/ozt) ÷ 20
You can quickly work out current conversions and the melt value of scrap gold in dwt with the unit converter or the melt value calculator.
Distinction from similar units
The pennyweight is exclusively part of the troy system and must not be confused with the avoirdupois system, which applies to everyday goods. Smaller units such as the tola (South Asian region, ≈ 11.66 g = 7.5 dwt) or the tael (East Asian region) are also regionally common, but not compatible with the pennyweight system.
In brief
One pennyweight equals exactly 1.55517 grams, or 1/20 of a troy ounce, and is the most common small unit in the Anglo-American jewellery and scrap-gold trade – anyone comparing offers there should have the simple formula "÷ 20 = troy ounces" to hand.