Compare a Scrap-Gold Offer in Pesos With a Dollar Melt Value

A seller who receives a scrap-gold offer in pesos often compares the number of pesos directly to the dollar spot price they see online. That comparison conflates currency conversion with purity, weight, and buyer-margin differences. The correct method is to convert the peso offer to dollars using a real exchange rate available to the seller, calculate the melt value of the gold in dollars, and then compare only the dollar amounts. That separation isolates the buyer's margin from the currency spread. To compare a scrap-gold offer in pesos with a dollar melt value, walk through one concrete example, recompute every step, and name the failure case that catches most newcomers.

Melt value is the intrinsic worth of the gold content in an item. The formula is weight in troy ounces multiplied by purity as a decimal multiplied by the current gold spot price in USD per troy ounce. The London Bullion Market Association sets the global standard for spot prices. The U.S. Mint defines the troy ounce as 31.1035 grams for precious metals. Purity is commonly expressed in karats: 24K equals 99.9 percent pure, 18K equals 75 percent, 14K equals 58.5 percent, and 10K equals 41.7 percent. The seller must verify the karat stamp or have the item tested by an assayer.

Take a 10-gram 14K gold chain. Convert grams to troy ounces: 10 grams divided by 31.1035 equals 0.3215 troy ounces. Purity is 58.5 percent, or 0.585 as a decimal. Assume the LBMA spot price is 2000 USD per troy ounce. Melt value in USD equals 0.3215 times 0.585 times 2000, which equals 376.16 USD.

A buyer offers 7000 MXN for the chain. The immediate instinct is to compare 7000 MXN directly to the 376.16 USD melt value, which is meaningless because the two amounts are in different currencies. Convert the peso offer to USD using an exchange rate that the seller can actually obtain. The exchange rate available to a seller in the US is not the mid-market rate seen on Google. The seller's bank or a casa de cambio will apply a spread of 1 to 3 percent above the mid-market rate. For this example, use 20 MXN per USD as the seller's realistic rate. Divide the offer: 7000 MXN divided by 20 equals 350 USD.

The scrap gold calculator now shows a clean comparison: the melt value is 376.16 USD, and the offer is 350 USD. The difference is 26.16 USD, which represents a 7 percent discount below melt value. The seller can evaluate that discount against typical buyer margins in the scrap gold market, which range from 5 to 20 percent depending on the buyer, refining costs, assay costs, and market conditions. A 7 percent discount on a small 10-gram item is reasonable.

Apply the same steps to any item. Weigh the gold in grams, convert to troy ounces, identify the karat, find the spot price, and compute melt value in USD. Then convert the peso offer using the exchange rate the seller can get, not the mid-market rate. Compare the two dollar amounts. The difference between the converted offer and the melt value is the buyer's margin. That margin includes profit, refining costs, assay costs, and market risk. The comparison works only when both amounts are in the same currency.

The calculation separates currency conversion from purity, weight, and buyer-margin differences by performing each step independently. Purity and weight determine the melt value in USD. The exchange rate converts the peso offer to USD. The buyer's margin is the difference between the converted offer and the melt value. No single step conflates the factors. The seller sees that a 7000 MXN offer equals 350 USD, which is 26.16 USD below melt value. Without the conversion, the seller only sees 7000 MXN versus 376 USD and cannot judge the fairness of the offer.

The failure case is comparing the peso offer directly to the dollar spot price without converting both to the same currency. A seller who sees 7000 MXN and 376.16 USD might assume the exchange rate is roughly 18.6 MXN per USD and think the offer is fair. That assumption conflates currency conversion with the buyer's margin. The seller accepts an offer that may be below melt value after the real exchange rate is applied. The only way to avoid this failure is to convert the peso offer to USD using the seller's actual exchange rate, then compare the dollar amounts.

The explanation is straightforward: convert both values to the same currency. The melt value is always in USD because the LBMA spot price is quoted in USD. The peso offer must be converted to USD using an exchange rate that reflects the seller's cost of converting pesos to dollars. The exchange rate should be the bank rate or casa de cambio rate available to the seller, not the mid-market rate. The difference between the converted offer and the melt value is the buyer's margin. The seller then decides if that margin is acceptable.

The method assumes the seller can obtain the exchange rate used in the conversion. In practice, the rate available to the seller may differ from the rate assumed in the example. A seller in the US converting pesos from a Mexican buyer may receive a rate from a US bank, which adds its own spread. The actual exchange rate could be 19.5 or 20.5 MXN per USD, which changes the converted offer by about 2 to 3 percent. The seller must use a real quote from their bank or a casa de cambio, not an assumed rate, to get a realistic comparison. The single thing that most often goes wrong is the seller using a mid-market exchange rate instead of the rate they can actually get, which understates the buyer's margin and leads to accepting a worse offer than the seller realises.