This will depend on the type of barbell. A typical 7ft Olympic barbell weighs 20kg. Barbells that are used in Powerlifting or Olympic Weightlifting competitions are 20kgs. Womens bars are 15 kgs.. These are two generally accepted standards. However, there are many other varieties of barbells. Some are shorter, some are longer, and some come in different designs. The weight of these barbells is different. Unlike the competition barbells, there is no universally accepted specification for say an Olympic EZ curl bar.