Scrap Silver Calculator by Purity

This calculator works out the value of scrap silver based on its weight and purity. You enter the weight in grams or ounces and select the purity (e.g., sterling 925, fine 999), and it returns the pure silver content and its estimated market value. The result is the melt value, not a dealer’s buy price, which is typically lower.

Formula

The melt value is calculated as:

Value (USD) = (Weight in grams ÷ 31.1035) × Purity × Silver price per troy ounce

• Weight – the total weight of the item in grams (or convert ounces to grams first).
• Purity – the fraction of pure silver in the alloy (e.g., 0.925 for sterling, 0.999 for fine).
• Silver price – the current spot price per troy ounce (1 troy oz = 31.1035 g).

The first step converts grams to troy ounces, because silver is traded in troy ounces. Then multiplying by purity gives the actual amount of pure silver, and finally by the price gives the dollar value.

Worked Example

Using the default values: weight = 100 g, purity = 0.999, price = $25.00/oz.

1. Convert to troy ounces: 100 ÷ 31.1035 = 3.2151 oz
2. Multiply by purity: 3.2151 × 0.999 = 3.2119 oz pure silver
3. Multiply by price: 3.2119 × 25.00 = $80.30

The calculator shows $80.30 as the melt value and 99.9 g as the pure silver content.

Why Purity Matters

Silver is rarely pure in everyday items. Sterling silver (925) contains 92.5% silver and 7.5% other metals, usually copper. Coin silver (900) is 90% silver. Many older items or those from certain countries use 800 silver (80%). The purity directly scales the value – a 100 g sterling item is worth only 92.5% of a fine silver item of the same weight. So knowing the exact purity is essential for an accurate estimate.

How to Determine Purity

Look for hallmarks or stamps on the item. Common marks include:

• 925 or Sterling – 92.5% silver
• 999 or Fine Silver – 99.9% silver
• 800 – 80% silver (common in European jewelry)
• Coin – often 90% for pre-1965 US coins

If no mark is visible, you may need an acid test or X-ray fluorescence (XRF) analysis to confirm purity. Do not assume an item is silver just because it looks shiny – many items are silver-plated over base metal.

Common Mistakes to Avoid

• Mixing up grams and ounces: Always use troy ounces for silver. A regular ounce is about 28.35 g, but a troy ounce is 31.1035 g. Using the wrong conversion can overvalue your silver by about 10%.
• Ignoring purity: Weighing a sterling item and treating it as pure silver overstates its value.
• Using the wrong spot price: Silver prices fluctuate daily. Use the current live spot price, not a historical or guessed number.
• Expecting the melt value as a buy-back price: Dealers pay below spot (often 70–90% of melt) to cover refining costs and profit. The calculator gives the theoretical metal value, not what you will receive.

Limits of the Melt Value

The melt value is a baseline. Actual offers depend on market conditions, the dealer’s margins, and the form of the silver. Coins or jewelry may carry numismatic or antique value above melt. Conversely, items with stones or non-silver parts must be weighed excluding those components, or the result will be too high. The formula assumes the entire weight is the silver alloy, so you must subtract the weight of any non-silver materials.

Frequently Asked Questions

How do I convert ounces to grams for silver?

If your weight is in avoirdupois ounces (the common kitchen ounce), multiply by 28.3495 to get grams. If it is in troy ounces (used for precious metals), multiply by 31.1035. Most household scales measure in avoirdupois ounces.

What is the difference between spot price and melt value?

Spot price is the current market price for one troy ounce of pure silver. Melt value is the calculated worth of the silver content in your item, based on its weight and purity. Melt value equals spot price multiplied by the pure silver amount.

Why do dealers pay less than melt value?

Dealers need to cover refining costs, transportation, and a profit margin. They also face market risk while holding inventory. Typical buy-back rates range from 70% to 90% of melt, depending on the item type and quantity.

Can I use this calculator for sterling silver flatware?

Yes, but you must weigh only the silver parts. Remove any handles made of non-silver materials (like wood or plastic) and any steel blades. Then select 925 as purity. The result will be the melt value of the silver in those components.

Is it worth selling scrap silver?

It depends on the amount and current prices. Small quantities may not be worth the effort after shipping or travel costs. For larger amounts, selling to a reputable dealer can yield a good return. Always compare offers from multiple buyers.

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in w | Weight | g | 100 | 0
sel p | Purity | 999=0.999, 925=0.925, 800=0.800, 500=0.500
in price | Silver price | USD/oz | 25.00 | 0
out value | Melt value | USD | (w / 31.1035) * p * price | 2
out pure | Pure silver | g | w * p | 2