Gold Weight Calculator

Enter your gold's weight, unit of measurement, karat purity, and gold price per troy ounce to calculate the pure gold weight and total gold value. The Gold Weight Calculator converts your input across grams, pennyweights, and troy ounces, applies your chosen karat's fineness, and returns the refined gold content alongside an estimated market value — perfect for scrap gold, jewelry projects, or investment planning.

Enter the total weight of your gold item.

Check your jewelry for a karat stamp (e.g. 18K, 14K). Use a gold testing kit if unstamped.

USD

Enter the current spot price of gold per troy ounce. Check a live gold price source for the latest rate.

%

Dealers often pay less than spot price. Enter a spread percentage if applicable (0 = full spot price).

Results

Total Gold Value

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Pure Gold Weight (Grams)

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Total Weight in Grams

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Total Weight in Troy Ounces

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Total Weight in Pennyweights

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Gold Fineness

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Gold Price per Gram (at Purity)

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Gold Purity Breakdown

Frequently Asked Questions

What do you mean by 18 karat gold?

18 karat gold means the alloy contains 18 parts pure gold out of 24 total parts, giving it a fineness of 0.750 or 75% pure gold. The remaining 25% consists of other metals like copper, silver, or zinc added to improve durability. 18K gold is one of the most common grades used in fine jewelry.

What is gold fineness and how does it differ from karat?

Gold fineness expresses purity as parts per thousand — for example, 18K gold has a fineness of 750, meaning 750 out of 1000 parts are pure gold. Karat is a related but older system measured out of 24 parts. Both describe purity: 24K = fineness 999, 18K = 750, 14K = 583, and so on.

How do I calculate the mass of a gold sheet or jewelry piece?

To calculate gold weight, you need the physical dimensions of the piece (length, width, thickness) and the density of your specific gold alloy. Multiply volume by density to get total mass, then multiply by the fineness (karat ÷ 24) to find the pure gold content. Our calculator handles the purity math once you enter your measured weight.

How do I find the karat value from the mass of gold?

The karat value can be found with the formula K = 24 × (mass of pure gold / total mass of the alloy). If you know the total weight and have tested the purity content, divide the pure gold mass by total mass and multiply by 24. Most jewelry is stamped with its karat value, or you can use a gold testing kit.

How much is gold worth per gram?

The value of gold per gram depends on the current spot price per troy ounce and the karat purity of the piece. Since 1 troy ounce equals 31.1035 grams, divide the spot price by 31.1035 to get the per-gram price, then multiply by the fineness ratio. For example, at $2300/troy oz, pure 24K gold is worth roughly $73.94 per gram, while 18K gold would be about $55.45 per gram.

What is a pennyweight (DWT) and how does it compare to grams?

A pennyweight (abbreviated DWT) is a unit of weight used in the precious metals and jewelry trade. One pennyweight equals 1.55517 grams, and there are 20 pennyweights in one troy ounce. Some jewelers and scrap gold buyers quote prices in DWT, so it's useful to be able to convert between units.

What is a price spread and how does it affect my gold's value?

A price spread (or dealer discount) is the difference between the spot market price of gold and the lower price a buyer actually pays for scrap or used gold. Dealers apply a spread to cover processing costs and profit margin. A 10% spread on $2300/oz spot means you'd receive $2070/oz equivalent. Enter your dealer's spread percentage in the calculator to see your realistic payout.

What scale should I use to weigh my gold at home?

A digital gram scale accurate to at least 0.1 grams is recommended for weighing gold at home. Dedicated jewelry scales that read to 0.01 grams offer even greater accuracy. Standard kitchen scales can give a rough estimate but may not be precise enough for small pieces. Affordable digital scales are widely available online for under $15.

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