Jewelers need to know how to determine how much gold is needed for a wax mold. Here are three methods for you:

METAL METAL/WAX RATIO
SILVER 10.5 – 1
GOLD 10K 13 – 1
GOLD 14K 14- 1
GOLD 18K 16 – 1
PLATINUM 22 – 1
WAX WEIGHT 1.0gm
GOLD 9K 11.2 gm
GOLD 14K 14.1 gm
GOLD 18K 15.7 gm
GOLD 22K 17.8 gm
GOLD 24K 19.5 gm

If your wax will fit in a graduated cylinder, the kind used in high school chemistry classes to measure liquids, then fill the cylinder with water to a specific level, say 30 ml in a 50 ml cylinder. Then put your wax in the water, making sure that there are no large bubbles clinging to it. Push it down completely below the surface of the water with a thin wire, something thinner than a paper clip. Make sure the wire enters the water off to one side of the cylinder.

Now read the new volume of the water plus wax, (read at the bottom of the meniscus.) Say you now read 37.5 ml. Remove the wire and gently pour out the water and the wax, being careful not to damage the wax.

Now fill the graduated cylinder up with water to 30 ml and add casting shot to the cylinder until the meniscus again reads 37.5. You now have exactly the correct amount of gold for that wax. Remember that any additional sprue, tree and/or button gold will have to be added to make the total amount of gold to be melted.