This invention relates to a selectorized dumbbell having a handle that can be dropped down between nested left and right stacks of weight plates. The weight plates can comprise individual weights or a pair of weight plates, one from each stack, can be connected together to form a single weight. A selector is provided to allow the user to select a desired number of weight plates from each stack and couple such weight plates to the handle to provide an adjustable weight dumbbell. Each weight plate comprises a pair of thinner or partial thickness weight subplates that are abutted and welded together, e.g. a 1/2'' weight plate is formed by a pair of 1/4'' weight subplates. This substantially decreases the cost of manufacturing the selectorized dumbbell.