Why small coins cost more per gram of gold

The gold in a coin is worth the same whoever struck it. Everything above that — the striking, the distribution, the shop — is charged per coin, not per gram, and that is the whole reason a small coin is dearer per gram than a big one.

Spot is the price of a gram of gold, and it is the same gram in every coin on this site. What a dealer asks above it is the premium: the mint’s work, the wholesaler, the shipping, the insurance, the shop’s own margin, and the fact that somebody had to hold the coin until you asked for it.

Almost none of that scales with the gold. Striking a 21 mm disc costs about what striking a 32 mm disc costs; posting one insured parcel costs what posting the other costs. Spread those fixed costs over 5.8064 grams of fine gold in a marengo and over 31.1035 grams in an ounce coin, and the small coin carries five times the share.

So the ranking is not a surprise: gram for gram the 50 pesos — 37.5 g of fine gold in a single coin — tends to be among the cheapest metal on the map, the one-ounce coins sit below the small European coins, and the 20-franc pieces, at 5.81 g, pay the most for their size.

Then why buy a small coin at all

Because a premium is a price for something, and divisibility is the something. Selling half an ounce of gold is straightforward if you hold four sovereigns and impossible if you hold one Krugerrand. A coin that half the continent recognises also sells faster, and sells closer to the quoted price, than a large coin a particular shop may not want that week.

Which is why this site compares premiums within a coin and not across coins. Across coins the cheapest gram is nearly always the biggest coin, and that answer is true and useless. Within a coin — the same object, forty shops — the spread is the dealer, and that is the number you can act on.

Every price on the map carries what it costs over spot, so the comparison is made on the metal rather than on the coin’s size. How that number is worked out is on the how it works page.