The basics

How the gold price per gram is calculated from the ounce price, with examples for every karat

Gold is priced worldwide in dollars per troy ounce, and every gram price in every currency is derived from it by one formula. We walk through it step by step with today's figures for 24K, 22K, 21K, 18K and 14K, and explain why a shop's price differs from the result.

By GoldUp2Date editorial teamPublished 29 October 20265 min read

How the gold price per gram is calculated from the ounce price

Every gold price you see, in a news bulletin, on a shop board or on this site, starts from a single number: the price of a troy ounce of gold in US dollars on the world market. From that number the price of a gram of any karat in any currency follows by one formula that never changes. Once you know it you can price any piece yourself, judge whether a shop's figure makes sense, and tell the movement of gold apart from the movement of your currency. This article walks through it step by step with today's figures.

The troy ounce, and why it is not the kitchen ounce

Gold is priced per troy ounce, which weighs 31.1034768 grams. It is not the avoirdupois ounce used for food (28.35 grams), so never use 28 in a gold calculation. The ounce price is quoted in US dollars because the largest trading centres (London and New York) deal in dollars and because the dollar is the settlement currency for metals. When you hear "the ounce is at 4,000 dollars", that means 31.1 grams of pure gold.

The basic formula: from the ounce to a gram of pure gold

The price of a gram of pure gold (24K) in dollars is the ounce price divided by 31.1035. In your currency:

24K gram price = (ounce price in USD ÷ 31.1035) × the dollar's exchange rate in your currency

With today's figures (November 7, 2026): the ounce is 4,072 dollars, so a gram of pure gold is 130.92 dollars. In pounds sterling (the dollar at 0.7487 GBP) it is £98.02, in Indian rupees (the dollar at 93.91 INR) ₹12,294.80, in UAE dirhams (a fixed peg of 3.6725) AED 480.81, and in Saudi riyals (a fixed peg of 3.75) SAR 490.95.

The second step: from pure gold to a karat

The karat states the share of pure gold in an alloy out of 24 parts. 18K means 18 parts gold and 6 parts other metals, a purity of 75%. Therefore:

Karat gram price = 24K gram price × (karat ÷ 24)

Notice that the ratio between any two karats is fixed whatever the price: a gram of 18K is always 75% of a gram of 24K and 85.7% of a gram of 21K.

A full example: a 12-gram chain of 18K

1. The ounce today is 4,072 dollars and the dollar is 0.7487 pounds.
2. A gram of 24K = 4,072 ÷ 31.1035 × 0.7487 = £98.02.
3. A gram of 18K = £98.02 × 0.75 = £73.52.
4. The gold in the chain = 12 × £73.52 = £882.19.

That is the "melt value" or raw price the jeweller starts from. The same chain is worth $1,178.29 in the United States and ₹110,653.17 in India. Convert any of the three back into dollars and they match: raw gold costs the same everywhere, and the whole difference is the exchange rate.

Local units: the ounce, the 10 grams, the tola, the sovereign

The same formula prices any unit once you know its weight of pure gold:

• The ounce in your currency = 24K gram × 31.1035, so £3,048.78 or ₹382,410.92 today.
• 10 grams of 22K (the quoting unit in India) = 22K gram × 10 = ₹112,702.30.
• The tola (Pakistan and India) = 11.6638 grams, so a tola of 24K = 24K gram × 11.664.
• The Sovereign = 7.32 g of fine gold, so its metal value = 24K gram × 7.32 = £717.51.
• The Egyptian gold pound = 8 g of 21K = 7 g of fine gold.

Why the shop's price differs from the result

Because the formula gives the value of the raw metal only, and the jeweller adds three things: the making charge (the cost of the work, per gram or as a percentage), the hallmarking fee (the purity stamp), and tax where it applies (20% VAT on jewellery in the UK, 15% in Saudi Arabia, 5% in the UAE, 3% GST plus 5% on making in India, 14% on the making charge only in Egypt), plus the shop's margin. When you sell, the opposite happens: the buyer pays the raw value less a deduction (3–10%) and nothing for the making. So a shop always shows two prices, a selling price above melt and a buying price below it, and the gap is the cost of getting in and out of gold.

A fourth factor appears in some markets: a local premium or discount. In India the local price carries import duty and local demand; in Egypt it can trade above the formula when dollars are scarce. Comparing the announced price with the computed one reveals the gap at once.

Spot, futures and the close

The formula uses the spot price, the price for immediate delivery that moves second by second during trading hours. You will also hear about futures (contracts for later delivery on the New York exchange), usually a little above spot because of financing costs until delivery, and about the closing price recorded at the end of the day and used to compute the daily change. The differences are a few dollars an ounce and change the gram price by cents.

When the market is closed

Gold trades from Sunday evening to Friday evening, New York time. Over the weekend the ounce stays at Friday's close, and the gram price in your currency stays put unless your exchange rate moves. Shops price the weekend on Friday's close and may add a cautious margin ahead of a volatile Monday opening.

Check it yourself in thirty seconds

Keep three numbers in mind: the ounce price, the dollar rate in your currency, and your karat's factor (0.75 for 18K). Multiply the ounce by the dollar rate, divide by 31.1, multiply by the factor: that is today's raw gram price for your karat. Compare it with the shop's figure; the difference should be the making charge and tax only. The price methodology page explains how the site applies this very formula live, and the currency converter gives the reference rate for any currency.

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