Gold Price Calculator: Value by Weight and Karat

About the Gold Price Calculator

The Gold Price Calculator answers a simple question: what is this piece of metal worth? Type the weight in grams, troy ounces or pennyweights, choose the purity as a karat or a fineness, and type today's spot price per gram or per troy ounce. The calculator shows the melt value, the weight of fine gold in the piece and the spot price per gram. It works for silver and platinum too: pick the metal and the purity presets change to match.

You type the spot price yourself. Gold prices move all day and differ by currency and market, and this page makes no request for prices, so nothing is ever out of date or tracked. The troy ounce and the pennyweight are converted with their exact definitions, and every typed decimal is held as an exact fraction, so the result rounds only once, half up, to the cent. That matters for small weights such as 0.15 g or 0.30 g, where floating-point maths can round the wrong way.

How to use it

The formula

With a weight $w$ in grams, a purity $p$ and a spot price $s$ per gram:

$$\text{value} = w \times p \times s, \qquad p = \frac{\text{karat}}{24} \text{ or } \frac{\text{fineness}}{1000}$$

One troy ounce is exactly 31.1034768 g and one pennyweight is 1.55517384 g. A price per troy ounce is divided by 31.1034768 to get the price per gram.

Worked examples

• 0.15 g at 85.00 a gram. 24K gives $0.15 \times 85 = 12.75$; 22K gives $0.15 \times \tfrac{22}{24} \times 85 = 11.6875$, so 11.69, from 0.1375 g of fine gold.
• 0.30 g of 18K at 85.00 a gram. $0.30 \times 0.75 \times 85 = 19.125$ exactly, which rounds up to 19.13.
• 0.08 g of 24K at 2,650.00 an ounce. $2650 \div 31.1034768 = 85.1995$ a gram, so the value is 6.82.
• 10 dwt of 14K at 2,650.00 an ounce. 10 dwt is half a troy ounce, so $0.5 \times \tfrac{14}{24} \times 2650 = 772.92$.

Assumptions

The result is melt value at the spot price you typed. Dealers and refiners usually pay less, and jewellery sells for more because of design and labour, so check a current quote; the result is an estimate. For the price per gram of anything else you buy, use the Price Per Gram Calculator, and to convert grams to ounces or other units, use the Mass Converter.

Privacy

Nothing is uploaded; every calculation runs in your browser and never leaves your device. The weights and prices you type stay on this page and are gone when you close or reload it.

Frequently asked questions