There are two types of commonly-used barbells: Olympic and standard. According to the Houston Chronicle, Olympic barbells typically weigh 45 pounds, while standard barbells are much lighter, weighing in at about 13 pounds.
Olympic barbells can range in weight from 35 to 45 pounds, notes the Houston Chronicle. Standard barbells can also vary slightly in weight. Olympic barbells are typically thicker than standard barbells, about 2 inches in diameter compared to 1 inch typically in standard.
The Houston Chronicle states that standard barbells are better for beginners, who are not going to be using extremely heavy weights. Olympic barbells are better for serious bodybuilders who are going to be adding significant amounts of weight to the bar. The sturdy Olympic barbell reduces the risk of flexing, which can cause plates to slip off and cause injury.