What exchange rate should I use to convert the MXN offer?

Use the rate the buyer applied. If the buyer did not state it, ask. Do not substitute a market rate from XE.com or OANDA unless you confirm the buyer used that same rate.

Can I compute melt value in MXN instead of USD?

Yes, but that would require converting the spot price from USD per troy ounce to MXN per troy ounce, which introduces the same exchange rate step. The method described here keeps everything in USD to avoid a second conversion.

What is a fair payout percentage for 14K gold?

60-80% of melt value is typical. Below 50% is a poor offer. The percentage varies by buyer, volume, and local market conditions.

What if the buyer used a different exchange rate than the one I find online?

The buyer's internal rate is the one that determines your offer. If it is significantly lower than the market rate, ask why. A 5% difference in rate changes the comparison by the same amount.

Does the weight include stones or non-gold parts?

No. Weigh only the gold. Remove stones and non-gold components before weighing, or subtract an estimate of their weight. A ring with a large stone contains less gold than its total weight suggests.

What if the buyer does not give me the exchange rate?

Ask for it in writing. If they refuse, that is a red flag. A buyer who does not disclose the rate or the karat used in the calculation makes it impossible to verify the offer.

Can I use this method for dental gold?

Yes, but be careful with the purity. Dental gold is typically 10K-18K, not 24K. If the item has a hallmark like 585 for 14K, use that. If not, have it tested. The ADA classifies alloys as high-noble (60%+ gold) or noble (25-60% gold), but a consumer cannot reliably guess the karat from appearance.

Convert a Gold Offer From Pesos to Dollars Explained

Convert a Gold Offer From that calculation

A seller who receives a scrap gold offer in Mexican pesos (MXN) and needs to compare it with a spot-value estimate in US dollars (USD) must keep the currency conversion entirely separate from the gold calculation. The melt value of the gold is weight × purity × spot price, all in troy ounces and USD. The buyer's payout percentage is applied after that. The conversion from MXN to USD is a separate arithmetic step that uses an exchange rate, not a percentage of melt value. To convert a gold offer from pesos to dollars, divide the MXN offer by the USD/MXN exchange rate the buyer actually used. If the buyer gave you the rate, use that. If not, ask for it. Using a market rate from XE.com or OANDA when the buyer used a different internal rate introduces a mismatch that looks like a poor payout when the problem is the rate, not the gold calculation.

Convert a Gold Offer From that calculation Example

A seller weighs a 14K gold chain at 10.0 grams on a scale that reads to 0.01 g. The spot price for gold today is 2,600 USD per troy ounce. The melt value is 10.0 g × (14/24) × 2,600 USD/oz ÷ 31.1035 g/oz = 487.82 USD. A fair payout at 70% of melt value would be 341.47 USD. The buyer offers 5,000 MXN. The buyer's internal USD/MXN exchange rate is 20.0. The converted offer is 5,000 MXN ÷ 20.0 = 250.00 USD. That is 250.00 / 487.82 = 51.3% of melt value, well below the 60-80% range typical for common karats. The seller now knows the offer is poor. The conversion used only the rate the buyer applied. No mixing of exchange rate and dealer margin occurred.

Check the arithmetic: 10.0 g × 0.5833 (14K purity) = 5.833 g of pure gold. 5.833 g ÷ 31.1035 g/oz = 0.1876 troy oz. 0.1876 oz × 2,600 USD/oz = 487.82 USD. 5,000 MXN ÷ 20.0 = 250.00 USD. All steps verified.

Convert a Gold Offer From that calculation Calculation

The calculation has three separate steps, and you must perform them in order. Step one: compute the melt value in USD. Step two: convert the MXN offer to USD using the buyer's exchange rate. Step three: divide the converted offer by the melt value to get the payout percentage.

Step One: Melt Value in USD

Weigh the item. For a 14K piece, purity is 14/24 = 0.5833. Multiply weight in grams by purity to get grams of pure gold. Divide by 31.1035 to get troy ounces. Multiply by the LBMA spot price per troy ounce. The result is the melt value in USD. This step uses no exchange rate and no MXN figure.

Step Two: Convert the MXN Offer

The buyer gave you an offer in pesos. Divide that number by the USD/MXN exchange rate the buyer used. If the buyer did not state the rate, ask. Do not substitute a different rate. The page-specific fact sheet example uses 5,000 MXN ÷ 20.0 = 250.00 USD. If the buyer used 19.0 instead, the offer would be 5,000 ÷ 19.0 = 263.16 USD. That is a different comparison. Using your own rate of 20.5 would give 5,000 ÷ 20.5 = 243.90 USD, making the offer look 3.8% worse than it actually is. The error is in the rate, not the gold.

Step Three: Compute Payout Percentage

Divide the converted offer by the melt value. In the example, 250.00 USD ÷ 487.82 USD = 0.513 = 51.3%. Compare this to the 60-80% range typical for common karats. A percentage below 50% is a poor offer.

Convert a Gold Offer From that calculation Explained

The reason the separation matters is that exchange rates and dealer margins are two different things. The dealer margin is the difference between the spot price and what the buyer pays you, which includes refining costs, profit, and overhead. The exchange rate is the price of one currency in terms of another. If you mix them, you cannot tell whether a low offer is caused by a bad gold payout or a bad exchange rate.

Failure case: A seller receives an offer of 5,000 MXN for a 10.0 g 14K chain. The seller computes melt value as 487.82 USD. Instead of dividing by the exchange rate, the seller multiplies: 5,000 MXN × 20.0 = 100,000 USD. That is absurdly high, but a seller in a hurry might not notice. The error comes from confusing the direction of conversion. The correct operation is division. The page-specific fact sheet warns that multiplying instead of dividing overstates the USD amount by the square of the rate, which in this case is 400 times.

Another failure case: The seller uses a market rate of 20.5 from XE.com, but the buyer used an internal rate of 19.0. The seller calculates 5,000 ÷ 20.5 = 243.90 USD, then divides by 487.82 to get 50.0%. The seller thinks the payout is 50%, but the buyer's actual conversion was 5,000 ÷ 19.0 = 263.16 USD, which is 53.9% of melt value. The seller walks away believing the offer is worse than it is, or negotiates based on a wrong number. The solution is to ask the buyer for the rate they applied and use that exact rate.

Limit of this method: The exchange rate fluctuates. The rate at the time of the offer may differ from the rate when the seller calculates the comparison. If the seller waits a day, the spot price may also change. The comparison is valid only at the moment the offer is made. Use the buyer's rate and the spot price from the same day, ideally the LBMA Gold Price for that date.

Who This Gold Conversion Method Suits and Who Should Skip It

This method suits a consumer with a few broken or unwanted jewellery pieces who needs to know if a cash-for-gold offer in pesos is fair. It also suits a small-scale reseller buying scrap from multiple sources who needs a consistent method to price lots by weight and karat without relying on buyer quotes. An educator producing consumer-finance content will find the formula and the separation rule useful. Anyone who inherited a collection of old jewellery or dental gold and wants to understand what the pieces are worth before selling should use this approach to compute a baseline.

Skip this method if you are a professional jeweller or refiner buying scrap in volume. You need a refining industry guide that accounts for refining loss, batch pricing, and contract terms. Skip it if you want to invest in gold bullion or coins as an asset. Bullion is sold at a small premium over spot, not at a percentage of melt value, and the currency conversion is handled by the dealer.