How JinglePig works out melt values, where our prices and coin specifications come from, and what the price labels mean.
The formula
Every melt value on JinglePig uses the same two steps:
- Pure metal = gross weight in grams × fineness ÷ 31.1034768 grams per troy ounce
- Melt value = pure metal in troy ounces × spot price per troy ounce
For bullion coins, where the mint states the pure-metal content (for example one troy ounce), we use the stated figure. Every coin page shows its math with today’s numbers.
Coin specifications
We record each coin’s standard minted weight and fineness, with the source and the date we checked it. Sources are mints and treasuries first (such as the US Mint and the Royal Canadian Mint), then standard numismatic references. Where a coin was made in more than one alloy, each version is listed separately so you can match your coin’s date and mint mark.
Melt values use the standard weight. Circulated coins have lost a little metal to wear, so a worn coin can hold slightly less than the figure shown.
Historic world coins (1850s–1960s) are checked against official records wherever they exist: the issuing country’s mint, central bank or coinage law, or the US Mint’s published tables of the foreign coins it struck. A coin’s page links its official source. Where no official record can be found online, a coin is published only if an independent reference agrees with its weight and purity; where records disagree we use the official figure, and coins we cannot confirm are left out until we can.
Spot prices
Prices come from JinglePig’s own price service, which checks a market data provider every few minutes and stores the result. Visitors’ browsers only ever ask JinglePig, never the provider. Prices are in US dollars per troy ounce.
Each price carries a label:
- Current quote: refreshed on schedule, and the market quote is recent.
- No new quote · markets may be closed: we checked on schedule but the market has not published a new price, which is normal on weekends and holidays.
- Out of date · refresh delayed: we have not been able to refresh the price recently; the last known price is shown with a warning.
- Manual price: an administrator has set the price by hand.
What melt value is not
Melt value is not an offer to buy or sell and is not a collector value. It is the value of the metal at spot price, and collectible coins can be worth much more than their metal. See our disclaimer.
Spotted an error in a specification? Please let us know through our contact page.