The Cup Holder Expander expands the capacity of undersized car cup holders to accommodate larger water bottle, cups, and mugs. The design inserts into the existing cupholder and extends upward. The design maintains the current shape for standard cups, but allows larger mugs and bottles to be placed in the upper area. The design is simple, removable, washable, and inexpensive. The lower part of the design is similar in size and taper as a standard disposable coffee mug, so it can be inserted into any standard cup holder.