Gold Value Calculator: Calculate Gold Worth by Weight and Purity
Gold is weighed and priced in troy ounces, a unit slightly heavier than a regular ounce. The value of any gold item depends on three things: its weight in troy ounces, its purity (how much of the weight is actually gold versus other metals), and the current spot price of gold per troy ounce. This calculator handles all three. Select your weight unit (troy ounces, grams, or pennyweights), enter the weight, choose the karat purity from the dropdown, and enter the current spot price from a live source such as COMEX or the London Bullion Market Association. The calculator converts your weight to troy ounces, applies the purity fraction to find the pure gold content, and multiplies by the spot price to give the gold value. Because spot prices change by the minute, this calculator intentionally does not provide a default price. Look up the current price, enter it, and the result reflects today's market. The value shown is the commodity (melt) value of the gold content, not a buy or sell quote from any dealer.
Formulas
Weight in troy oz:
- If grams: weight / 31.1035
- If pennyweights (dwt): weight / 20
- If troy oz: weight (no conversion)
Pure gold (troy oz) = weight_troy_oz × purity_fraction
Pure gold (grams) = pure_gold_troy_oz × 31.1035
Gold melt value ($) = pure_gold_troy_oz × spot_price_per_troy_oz
Purity reference
| Karat | Gold fraction | Gold % | Common use |
|---|---|---|---|
| 24k | 24/24 | 99.9% | Bullion coins and bars |
| 22k | 22/24 | 91.67% | American Gold Eagle coins, some jewelry |
| 18k | 18/24 | 75.0% | Fine jewelry (Europe and Asia) |
| 14k | 14/24 | 58.33% | Common US jewelry |
| 10k | 10/24 | 41.67% | Economy jewelry (minimum legal "gold" in US) |
Weight conversion reference
1 troy ounce = 31.1035 grams = 20 pennyweights (dwt)
1 pennyweight (dwt) = 1.55518 grams
1 gram = 0.03215 troy ounces
How to use this calculator
- Look up the current gold spot price per troy ounce from a live source such as the LBMA, COMEX, or a financial data provider. Enter that price in the spot price field.
- Enter the weight of your gold item and select the unit (troy ounces, grams, or pennyweights).
- Select the karat purity. If you are unsure, look for a hallmark stamp on the item (e.g., "18K", "750", or "585").
- The calculator shows the weight in troy ounces, the pure gold content, and the melt value. Results update as you type.
- Note that dealers buy scrap gold below melt value and sell fabricated items above it. The melt value is the theoretical raw commodity value only.
Frequently asked questions
What is a troy ounce?
A troy ounce is the standard unit of weight for precious metals. It is equal to 31.1035 grams, which is slightly heavier than a regular (avoirdupois) ounce of 28.3495 grams. Gold, silver, platinum, and palladium prices are all quoted per troy ounce globally.
What does karat mean for gold?
Karat (abbreviated k or kt) measures gold purity as a fraction of 24 parts. Pure gold is 24k (99.9% gold). 18k gold is 18/24 = 75% gold and 25% other metals (typically copper, silver, or zinc for strength and color). Lower karat jewelry has more alloy content and less gold value per gram.
Where can I find the current gold spot price?
The gold spot price is the current market price for one troy ounce of pure (24k) gold for immediate delivery. It is quoted in real time on commodity exchanges (COMEX in New York, LBMA in London). Financial websites, your broker's platform, and the World Gold Council website publish live and recent prices.
What is the difference between spot price and melt value?
The spot price is the raw commodity price for pure gold. The melt value (or intrinsic value) is the spot-price-based value of the gold content in a specific item. Jewelry, coins, and bars sell above melt value because of fabrication costs and dealer premiums. Scrap gold dealers buy below melt value to cover refining and processing costs.
Are gold coins worth more than their melt value?
Most official bullion coins (American Gold Eagle, Canadian Maple Leaf, South African Krugerrand) trade at a small premium above melt value, typically 2% to 10% depending on market conditions and coin size. Numismatic (collectible) coins can trade far above melt value based on rarity, condition, and collector demand.
Official sources
- US Mint: Gold bullion coins: usmint.gov/learn/coin-and-medal-programs/bullion-coins
- LBMA: Precious metal prices: lbma.org.uk/prices-and-data/precious-metal-prices
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.