All gold bars stored at a US treasury site weigh the same.The standard weight of a gold bar at the United States Bullion Depository, at Fort Knox, Kentucky is exaclty 400 ounces or 27.5 pounds. According to the United States Mint, gold bars stored at the U.S. Treasury weigh 400 ounces on average. This translates to 27 ½ pounds per bar.