Gold bar 1 g or Gold bar 2.5 g: which is the better buy today?

Gold bar 1 g and Gold bar 2.5 g are the same object at two sizes — 999.9 gold from an LBMA refinery, with the weight on the stamp — and Gold bar 2.5 g holds 2.50 times the gold of Gold bar 1 g: 2.50 g against 1.00 g. The metal costs the same per gram in both; what differs is how much of the price is the making rather than the gold, and the small one always carries more of it.

Gold bar 1 g — The smallest bar there is: a gram of gold in a sealed card the size of a credit card, and more card than gold in the price — the making is paid once, on a gram.

Gold bar 2.5 g — Two and a half grams, a size the Swiss refineries made standard: still a gift more than an investment, and priced like one.

Both are 999.9 fine gold, cast or minted by a refinery on the LBMA Good Delivery list — PAMP, Valcambi, Argor-Heraeus, Heraeus, Metalor — and stamped with their weight and a serial: the same object at two sizes, and nothing between them but the number on the stamp.

What decides between them is not the gold, which costs the same per gram in both, but what is paid per bar: the minting or the casting, the assay card, the shop’s margin. Spread over 1.00 g the small one carries far more of it per gram than the big one does over 2.50 g — which is why Gold bar 1 g is nearly always the dearer gold, and why it is bought anyway: it sells in smaller pieces, in one go.

So the comparison is the premium. Whichever of the two a dealer asks less for above its metal is the cheaper gold that day — and that changes shop by shop and day by day, which is what the numbers above are for.