Formula Used
Purity from karat: purity percent = karat ÷ 24 × 100.
Purity from fineness: purity percent = fineness ÷ 1000 × 100.
Pure metal mass: pure mass = total mass × purity fraction.
Alloy mass: alloy mass = total mass − pure metal mass.
Moles: moles = pure metal mass ÷ molar mass.
Atoms: atoms = moles × 6.02214076 × 10²³.
Payable value: payable value = pure mass × recovery × remaining fraction × price per gram.
How to Use This Calculator
Enter a sample name and choose gold or silver.
Add the mass, quantity, and mass unit.
Select karat, fineness, or percent as the purity type.
Enter price per gram and your currency label.
Add recovery and refining loss values if needed.
Enter target purity to estimate alloy adjustment.
Press Calculate to show results above the form.
Use the CSV or PDF buttons to save the result.
Example Data Table
| Example |
Metal |
Mass |
Purity input |
Purity percent |
Pure mass |
| 18K ring |
Gold |
10 g |
18 karat |
75% |
7.5 g |
| Sterling chain |
Silver |
25 g |
925 fineness |
92.5% |
23.125 g |
| Pure bar |
Gold |
1 troy ounce |
999.9 fineness |
99.99% |
31.1004 g |
Gold and Silver Chemistry Calculator Guide
Gold and silver are measured by mass, purity, and chemical amount. This calculator links jewelry terms with laboratory chemistry. It converts karat, fineness, or percent purity into pure metal mass. It also estimates moles, atoms, volume, alloy content, and value. These results help students, jewelers, and buyers compare samples.
Why Purity Matters
A precious metal item is rarely completely pure. Gold jewelry may be 24K, 22K, 18K, 14K, or lower. Silver is often listed as 999, 925, 900, or 800 fineness. Purity tells how much of the sample is gold or silver. The rest is alloy material. That alloy may include copper, zinc, nickel, or other metals. In chemistry, purity affects molar amount and atom count. In trade, purity affects melt value and refining return.
Main Calculations
The tool first converts the entered mass into grams. It then reads the chosen purity system. For karat, the fraction is karat divided by 24. For fineness, the fraction is fineness divided by 1000. For percent, the fraction is percent divided by 100. Pure metal mass equals total mass multiplied by purity fraction. Alloy mass equals total mass minus pure metal mass. Moles equal pure mass divided by atomic molar mass. Gold uses 196.96657 grams per mole. Silver uses 107.8682 grams per mole. Atoms equal moles multiplied by Avogadro’s constant. Volume is estimated with density.
Value And Recovery
The price result uses the pure metal mass and price per gram. Refining loss and recovery rates can be entered. These options model real processing losses. A high recovery percentage raises expected return. A refining loss lowers payable mass. The final value is a practical estimate. It is not a live market quote. Use your own current spot price or buyer rate. The calculator keeps every step visible. That makes the result easier to check.
How This Helps
This calculator is useful for class problems and estimates. It can compare 18K gold with sterling silver. It can also show how many moles are in a sample. The target purity section gives blending guidance. It estimates pure metal addition for upgrading. It estimates base alloy addition for dilution. Always confirm important buying, refining, or assay decisions with a trusted professional.
FAQs
1. What does this calculator measure?
It measures pure metal mass, alloy mass, moles, atoms, volume, and value for gold or silver samples using entered purity and price data.
2. Can I use karat for silver?
You can enter karat for any sample, but karat is mainly used for gold. Silver is usually described with fineness, such as 925 or 999.
3. What is fineness?
Fineness shows pure metal parts per thousand. A 925 silver item contains 925 parts silver and 75 parts other alloy per thousand parts.
4. Why does value use payable mass?
Payable mass adjusts pure metal mass by recovery and refining loss. It gives a more practical estimate than raw melt value.
5. Are market prices updated automatically?
No. Enter your own price per gram. This keeps the calculator flexible for local rates, spot prices, or buyer offers.
6. What molar mass is used for gold?
The gold calculation uses 196.96657 grams per mole. This converts pure gold mass into chemical amount.
7. What molar mass is used for silver?
The silver calculation uses 107.8682 grams per mole. This converts pure silver mass into moles and atoms.
8. Is the target purity result exact?
It is a mathematical estimate. Real alloying may need assay checks, melting control, and professional refining methods.