How is the Worth of Gold Bars Determined?

The value of a gold bar depends on two main factors: its weight and the current spot price of gold. But there’s a lot more to it than just that. How much a gold bar is worth can also depend on premiums, market demand, and the type of bar being purchased.

In this guide, we explore what gold bars are, the factors that influence their price, what affects gold prices, and how gold prices are set.

What is a gold bar?

Gold bars, also called gold bullion, are solid blocks of refined gold with a minimum purity of 99.5%. These bars come in various weights and sizes, from small 1 gram gold bars to larger 1 kilogram bars and 400 oz ‘Good Delivery’ bars, giving different investors an option that meets their budget and preferences.

Gold bars are produced by sovereign mints, such as the Perth Mint, as well as private refineries like PAMP Suisse or Valcambi. Smaller gold bars are made through a minting process, using heavy machinery to create uniform blocks with straight edges, while larger bars are cast by pouring molten gold into molds, creating a more traditional and ‘rugged’ appearance. Each gold bar is stamped with the item’s weight and purity, the refinery/mint’s hallmark, and a unique serial number that verifies authenticity.

There are many uses for gold bars, including:

• Commercial finance instrument: Some large institutions add gold bars to their portfolios as a way to strengthen their financial position
• Personal asset: Individual investors purchase gold bars as a long-term store of value, helping protect purchasing power and diversify portfolios
• Reserve currency: Central banks around the world buy and store gold bars to protect against currency devaluation.

Learn More: Why Central Banks Buy Gold

How much do gold bars weigh?

Gold bars are available in various weights that make gold investment accessible to beginners with small budgets all the way up to institutional investors with large holdings.

Some common gold bar weights include:

• 1 gram gold bars: Popular for new investors looking for an entry point into gold
• 2 gram gold bars: Appeal to those who want to slowly build their holdings with smaller sizes
• 5 gram gold bars: A popular choice for gifting gold
• 10 gram gold bars: Mid-range bars that offer a balance between value and affordability
• 20 gram gold bars: Can substantially increase a portfolio's values while remaining easy to store and carry
• 50 gram gold bars: At this size, gold bars can be either cast or minted
• 100 gram gold bars: One of the most popular sizes for investors
• 250 gram gold bars: Only available in cast forms
• 500 gram gold bars: Provide substantial amounts of gold with lower premiums than smaller bars
• 1 kilogram gold bars: Favoured by institutional investors and those who wish to purchase large amounts of gold
• 100 oz & 400 oz gold bars: Larger sizes that are usually purchased by banks, investment funds, and governments. The 400 oz London Good Delivery bar is the global standard for wholesale trading and central bank reserves.

See: What are the Types of Gold Bars?

How much is a gold bar worth?

The value of a gold bar depends on gold’s current spot price (its real-time market value). Just like any other commodity, gold’s price isn’t fixed but fluctuates constantly in response to supply, demand, and global market conditions. To know how much their investments are currently worth, gold investors track gold’s spot price, which is the live trading price for one troy ounce of gold on international markets.

See More: Troy Ounce: Definition, History, and Conversion Table

The main factors affecting the value of a gold bar include:

• Spot price: The benchmark wholesale price used to trade 400 oz London Good Delivery bars between banks. Individual investors usually pay a premium above this price, with smaller bars and gold coins carrying higher premiums compared to larger bars.
• Gold content & purity: Gold’s spot price is based on pure 24-carat gold, so the value of a bar will depend on its actual content and purity. According to the London Bullion Market Association (LBMA), investment-grade gold bars must have a minimum purity of 99.5%. The higher the purity of a gold bar, the higher its value (e.g. 99.99% pure gold bars will be worth more than 99.9% pure because it contains more gold).
• Weight: Of course, the more a gold bar weighs, the more it will be worth since it means there’s a higher gold content.
• Investor demand: When there are imbalances between gold demand and supply, premiums (the extra cost above spot price) can increase and make gold bars more expensive.

How to calculate the value of your gold bar

To work out how much a gold bar is worth, multiply its gold content (in troy ounces) by the current spot price. For example, if gold is trading at $3,500 per troy ounce, a one kilo bar (32.1507 troy ounces) would be worth about $112,527.

That said, when you’re buying gold bars you’ll be paying a premium over the spot price. These premiums cover the costs of refining, minting, distribution, and any dealer overheads. Smaller bars tend to have higher premiums because their production costs make up a larger share of their overall price. Larger bars usually have lower premiums, which is why they’re more cost-efficient for investors buying in bulk.

What factors affect gold prices?

Gold prices are based on a combination of supply and demand, global economics, and investor sentiment.

Supply and mining production

Gold mining only adds about 2-3% to the world’s above-ground supply each year, so changes in demand often have a bigger influence on gold prices than changes in supply. Still, things like production costs, environmental regulations, and new deposit discoveries can impact future supply and put pressure on gold prices.

Central bank reserves

Collectively, central banks hold about one-fifth of all the gold ever mined. With such massive holdings, these institutions can significantly move the market when they buy or sell gold. In recent years, we’ve seen many emerging economies increase their gold holdings in an attempt to diversify away from the U.S. dollar, which has helped push global gold prices higher.

Inflation & the U.S. dollar

Gold is a dollar-denominated asset – it’s priced in U.S. dollars – and often moves in the opposite direction of the dollar. When the dollar is weaker, gold becomes more affordable for overseas buyers, increasing demand. On the other hand, a stronger dollar often pushes prices down.

Inflation can also affect gold prices. When interest rates are low, the opportunity cost of holding gold decreases, since gold doesn’t pay any interest or dividends. This makes it more attractive to investors and can push prices up. When interest rates rise, gold often becomes less appealing compared to interest-bearing assets, and demand may fall. That said, this isn’t always the case. In the mid-2020s, for example, we’ve seen gold prices soar despite higher rates or easing inflation.

Read More: Relationship Between the U.S. Dollar and Gold Prices

Economic uncertainty

Investors often turn to gold for stability during periods of economic turbulence or geopolitical tensions. That’s why gold is often referred to as a safe-haven asset. Its tangible nature and negative correlation with stocks & bonds provides a form of insurance against systemic risks that could impact traditional investment portfolios. For that reason, we often see gold prices increase when other assets fall.

Investor demand

Gold exchange-traded funds (ETFs) offer an easy way for investors to gain exposure to gold prices without needing to buy and hold physical gold bars or coins. These funds are bought and sold on exchanges just like stocks. When more investors buy shares in ETFs, the funds buy and store gold bullion to back up their shares, creating a direct link between fund flows and gold demand.

As of 26 September 2025, SPDR Gold Shares (GLD) is the largest gold ETF in the world with $107.76 billion in net assets.

Consumer demand (jewellery & technology)

The jewellery sector is the largest single source of gold demand, accounting for about half of annual consumption. In countries like China and India, gold jewelry is used as both adornment and a store of wealth, and demand often spikes during festivals and wedding seasons.

On the industrial side, gold’s excellent conductivity and corrosion-resistance makes it essential in certain electronics and medical devices. When industrial demand increases, gold prices are likely to increase with it.

Learn More: What Drives the Price of Gold?

What determines gold’s spot price?

We’ve learned the factors that affect gold prices, but who or what actually determines what gold is worth?

1. Over-the-counter (OTC) trading

Most gold trading happens on the OTC market, where banks, refineries, and large institutions deal directly with one another. The London market, in particular, is the biggest hub for OTC gold trading in the world, where 400 oz Good Delivery bars are exchanged privately between counterparties.

Because these trades aren’t visible to the public, investors and precious metals dealers often turn to data services like Bloomberg, Reuters, or the LBMA’s daily ‘fix’ to gauge where the OTC spot price currently stands.

2. Futures exchanges

Public futures markets, like the COMEX in New York, also play a role in determining gold prices. Futures are contracts that allow investors to agree on a price for gold to be delivered at a future date. Sometimes, futures prices are quoted as gold’s current price, however this is technically incorrect since they’re settled on a future date, while spot prices refer to the current market price.

That said, since futures prices are transparent and traded on regulated exchanges, they can be easier to track than OTC deals.

3. The LBMA

The London Bullion Market Association (LBMA) plays an essential role in setting gold prices. Each day, members of the LBMA meet at 10:30 a.m. and 3:00 p.m. London time to discuss and establish a ‘fair’ price of gold that reflects global supply and demand. This is known as the LBMA daily fix, and the established price then serves as a reference point for banks, refiners, and dealers around the world.

Learn More: LBMA: All You Need to Know

Buy investment-grade gold bullion bars

If you’d like to join central banks in investing in the timeless value of gold, there’s no better way to do it than with gold bullion bars. These investment-grade gold bars are made with at least 99.5% pure gold and carry lower premiums compared to buying gold coins.

At StoneX Bullion, we offer a wide selection of gold bars from the most prestigious mints and refineries in the world. Whether you’re starting your journey with a 1 gram gold bar or growing your portfolio with a 1 kilogram bar, you’ll find the right option to suit your goals. Browse our range of gold bars and start growing your wealth today.