Build a Target-Karat Batch
Calculate fine gold and total alloy requirements.
This is a mass-balance calculation. It does not specify the individual non-gold metals in the alloy.
Gold Alloy Mixing Formula
Pure Gold = Final Batch Weight × Fine Gold Fraction
Non-Gold Alloy = Final Batch Weight − Pure Gold
For example, 18K corresponds to 18/24, or 75% fine gold by mass. The remaining 25% is the non-gold alloy portion.
Why the Alloy Portion Is Not a Single Universal Recipe
Karat defines gold content, not the complete alloy chemistry. The remaining portion can contain different metals depending on the required color, hardness, casting behavior, corrosion resistance and other manufacturing requirements.
Example: 100 g of 18K Gold
100 − 75 = 25 g non-gold alloy
So a theoretical 100 g batch at 18K contains 75 g fine gold and 25 g of other alloy metals by the standard karat relationship.
Process Loss vs Target Batch Weight
A production process may involve handling or melting losses. The optional loss field increases the starting batch requirement so that the target finished amount can still be achieved.
This is a planning assumption, not a universal manufacturing loss rate.
Frequently Asked Questions
How do you calculate a gold alloy batch?
Multiply final batch weight by target karat divided by 24 to obtain the fine-gold requirement.
What does 18K gold mean?
18K corresponds to 18 parts gold out of 24, or 75% gold by mass.
How much pure gold is needed for 22K?
22K corresponds to approximately 91.6667% fine gold.
Can this determine exact alloy metals?
No. It only calculates total non-gold alloy mass.
Is 24K treated as an alloy here?
At 24K, the theoretical non-gold portion is zero.