A standard gold brick weighs approximately 400 troy ounces. The London Bullion Market Association, which sets the standards for the makeup of gold bricks, recommends that the weight of a gold bar should be a minimum of 350 fine ounces and a maximum of 430 fine ounces.
Since the brick-making process makes it difficult to have a consistent weight of 400 troy ounces, the London Bullion Market Association sets a narrow range that molders must conform to. However, most gold bars are close to 400 ounces. Traders multiply the weight of a bar of gold with its purity level to determine the actual fine gold content of the bar.