A dumbbell and barbell supporting system includes two tables movable toward and away from each other and each having a plate, a casing and a bracket disposed on each of the plates and the bracket being movable and rotatable relative to the casing, two dumbbells disposed on the tables and each including two weight members and two weight elements disposed on the bracket and the casing, and two handlebars engageable with the weight members and the weight elements, the weigh members are movable toward each other, and the weight elements also movable toward each other, and a longitudinal bar is engageable with the weight members and the weight elements for acting as a barbell device.