Calculate Resulting Gold Karat
Weighted fine-gold calculation for multiple batches.
The result assumes each input batch is accurately represented by its stated karat and measured weight.
How Mixed-Karat Gold Is Calculated
A simple arithmetic average of karat numbers is not correct when the batches have different weights. The correct calculation uses the fine-gold mass contained in each batch.
Total Fine Gold = Sum of Fine-Gold Masses
Resulting Karat = (Total Fine Gold ÷ Total Weight) × 24
Why Weight Matters
For example, 100 g of 22K gold has a much greater influence on the final mixture than 10 g of 22K gold. The weights therefore have to be included when determining the resulting karat.
Worked Example
Combine 100 g of 22K gold with 50 g of 18K gold.
18K Fine Gold = 50 × 18 ÷ 24 = 37.500000 g
Total Fine Gold = 129.166667 g
Total Weight = 150 g
Resulting Karat = 129.166667 ÷ 150 × 24
= 20.666667K
Mixed-Karat Gold vs Alloy Chemistry
The resulting karat describes overall fine-gold content. It does not identify how the non-gold portion is distributed among copper, silver, zinc, palladium or other metals.
Therefore, two mixtures with the same calculated karat can still have different color, hardness, density and manufacturing characteristics.
Mass Balance and Rounding
The calculator keeps the mathematical result at full JavaScript numeric precision during the calculation and rounds only displayed values. This reduces rounding error when several batches are combined.
Important Limitations
This is a fine-gold mass-balance calculator. It does not model refining losses, solder, impurities, oxidation, chemical reactions or changes in individual alloy chemistry.
Frequently Asked Questions
How do you calculate the karat of mixed gold?
Calculate fine-gold mass for each batch, add the fine-gold masses, divide by total weight and multiply by 24.
Can mixing different karats produce a new karat?
Yes. The resulting karat depends on the weighted fine-gold content.
Is the calculation based on weight or volume?
It is based on mass or weight.
Can I mix more than two karats?
Yes. This calculator supports up to four batches.
Does this determine the individual alloy metals?
No. It determines overall gold content only.