Scrap Gold Calculator Formula: Weight, Purity, and Spot Price

The scrap gold calculator formula estimates melt value using three core inputs: weight, purity, and gold spot price. Once you know these values, you can estimate the pure gold content and the approximate metal value of scrap jewelry.

For quick results, use the Calzivo Scrap Gold Calculator. It applies the formula automatically after you enter weight, karat, units, and price assumptions.

What Is the Scrap Gold Calculator Formula?

Simple Definition

The formula estimates the value of the pure gold content inside a scrap gold item.

What the Formula Estimates

It estimates melt value, which is the value of the gold metal content before buyer payout, refining costs, testing adjustments, or dealer margin.

Why Weight, Purity, and Spot Price Matter

Scrap gold value depends on:

• how much the gold weighs
• how pure the gold is
• the current gold price
• the unit used for weight and price

Scrap Gold Melt Value Formula

Melt Value = Gold Weight x Gold Purity x Gold Spot Price

Melt Value = Weight x Purity x Gold Price Per Unit

What Gold Weight Means

Gold weight is the measured weight of the gold content. For jewelry, the total weight may include stones, clasps, enamel, springs, or other non-gold parts.

What Gold Purity Means

Purity tells you what portion of the item is pure gold. Karat is the common purity system used in jewelry.

What Gold Spot Price Means

The spot price is a market reference price for pure gold. It is commonly quoted per troy ounce, but calculators may convert it to price per gram.

Why the Result Is an Estimate

The formula estimates metal value. Actual offers can differ because of testing results, buyer payout, fees, and market movement.

Step 1: Find the Gold Weight

Weigh Gold in Grams, Pennyweights, or Troy Ounces

Scrap gold may be weighed in grams, pennyweights, or troy ounces. The calculator unit must match the unit you use.

Remove Stones, Clasps, or Non-Gold Parts When Possible

If the item includes non-gold parts, the estimate may be too high if those parts are included in the weight.

Why Regular Ounces and Troy Ounces Are Different

Precious metals are commonly priced in troy ounces. A regular ounce and a troy ounce are not the same.

How Unit Conversion Affects Melt Value

Wrong unit conversion can create a large error. Use the Unit Converter before calculating if you are unsure.

Step 2: Convert Karat to Purity

Karat Purity Formula = Karat / 24

Purity = Karat / 24

10K Gold Purity

10 / 24 = 0.4167

10K gold is about 41.67% pure gold.

14K Gold Purity

14 / 24 = 0.5833

14K gold is about 58.33% pure gold.

18K Gold Purity

18 / 24 = 0.75

18K gold is 75% pure gold.

22K and 24K Gold Purity

22 / 24 = 0.9167
24 / 24 = 1.00

22K is about 91.67% pure. 24K is treated as pure or nearly pure gold for basic estimates.

Step 3: Use the Current Gold Spot Price

Spot Price Per Troy Ounce

Gold spot price is commonly shown per troy ounce.

Gold Price Per Gram

Many jewelry calculations use price per gram. Make sure the conversion is correct before using the formula.

Why gold prices change

Gold prices move with market conditions. An estimate can change from one day to another.

How Spot Price Affects Scrap Gold Value

Higher gold price increases the estimate. Lower gold price reduces it.

Step 4: Calculate Pure Gold Content

Pure Gold Weight = Total Weight x Purity

Pure Gold Weight = Total Weight x Purity

Example: Pure Gold Content in 14K Jewelry

Assume:

Total Weight = 20 grams
Karat = 14K

Calculation:

Purity = 14 / 24 = 0.5833
Pure Gold Weight = 20 x 0.5833 = 11.666 grams

Why Mixed Karats Should Be Calculated Separately

Do not average 10K, 14K, and 18K items together. Each karat group should be calculated separately.

Step 5: Estimate Final Melt Value

Multiply Pure Gold Weight by Gold Price

Melt Value = Pure Gold Weight x Gold Price

Example: Scrap Gold Melt Value in Grams

Assume:

Pure Gold Weight = 11.666 grams
Gold Price = $70 per gram

Calculation:

Melt Value = 11.666 x 70 = $816.62

Example: Scrap Gold Melt Value in Pennyweights

If your scale uses pennyweights, use a calculator that accepts pennyweights or convert correctly before applying the formula.

Example: Multiple Items With Different Karats

Calculate each group:

10K group value = $250
14K group value = $500
18K group value = $700

Total Melt Value = $1,450

Melt Value vs Buyer Payout

Why Melt Value Is Not the Same as a Cash Offer

Melt value estimates metal content. A buyer payout is the amount a buyer offers after costs and margin.

Refining Fees and Dealer Margins

Refining, handling, and profit margin can reduce the buyer offer.

Assay or Testing Adjustments

Testing may show different purity than expected, which can change the offer.

Buyer Payout Percentage Explained

If melt value is $800 and the buyer pays 90%:

Buyer Payout = 800 x 0.90 = $720

Use the Percentage Calculator to check payout rates.

Common Scrap Gold Formula Mistakes

Using Total Jewelry Weight Without Purity Adjustment

The full item weight is not pure gold unless the item is 24K.

Mixing Different Karats Together

Different karats must be calculated separately.

Confusing Troy Ounces With Regular Ounces

Use the correct precious-metal unit.

Using an Outdated Spot Price

Gold prices change, so use a current price.

Expecting Spot Value as the Final Offer

Buyer offers may be below melt value.

FAQs

What is the formula for scrap gold value?

Scrap Gold Value = Weight x Purity x Gold Price

How do I convert karat to gold purity?

Divide the karat number by 24.

How do I calculate pure gold weight?

Multiply total item weight by purity.

Should I use grams, pennyweights, or troy ounces?

Use the unit that matches your scale and calculator. Make sure the gold price uses the same unit or is converted correctly.

Why is a buyer offer lower than melt value?

The offer may include payout percentage, refining fees, testing adjustments, dealer margin, and transaction costs.

Final Note

The scrap gold formula is simple, but the inputs must be accurate. Sort by karat, use the right unit, check current gold price, and remember that melt value is not always the final cash offer.

Use the Calzivo Scrap Gold Calculator for quick melt value estimates.