How much can I get for my modern gold coins?

Many nations mint bullion coins, of which the most famous is probably the gold South African Krugerrand. Although nominally issued as legal tender, these coins' face value as currency is far below that of their value as bullion. For instance, Canada mints a gold bullion coin (the Gold Maple Leaf) at a face value of $50 containing one troy ounce (31.1035 g) of pure 24K gold. Bullion coins' minting by national governments gives them some numismatic value in addition to their bullion value, as well as certifying their purity.

The level of purity varies from issue to issue. 99.9% purity is common. The purest mass-produced bullion coins are in the Canadian Gold Maple Leaf series, which go up to 99.999% purity. Note that a 100% pure bullion is not possible, as absolute purity in extracted and refined metals can only be asymptotically approached. Usually a bullion coin contains a stated quantity (such as one troy ounce) of the slightly-impure alloy; the Krugerrand is unusual in containing one troy ounce of actual gold, with the impurity making the coin heavier than one ounce.

When you go to sell your modern gold coins to a dealer, you will receive a percentage of their full value. You will NOT receive 100% of the value, because dealers must make a profit in order to stay in business. The percentage of full value (called the spot value or spot price) will vary widely from dealer to dealer. Dealeres will offer anywhere from 80% to 90% of the "spot" price for your coins. Obviously, the higher percentage you can get, the better for you.

Another factor you must consider before you start doing the math is the "purity" of the coin you are selling. Not all modern gold coins are pure gold. Most are 24K gold, but some are only 22K. For purposes of simple calculation, we will consider pure 24K gold coins. If a dealer is offering to pay you 90% of spot, here is how to calculate the actual price he is offering:
1. Get the current spot price (from a site like www.metals-quote.com).
2. Multiply that price by the percentage the dealer is offering you.

Let's say the current spot price is $900.00 per ounce and you have a one ounce 24K gold coin for sale. The dealer has offered you 90% of spot for it. Simply multiply $900 X .90 (or $810) to get the price he is actually offering.