A 10x20 self storage unit is similar in size to a one-car garage, measuring 10 feet wide, 20 feet long, and 8 feet tall. With 1,600 cubic feet of space, it can accommodate the contents of a multi-room house. Items like king-size bedroom sets, dressers, mattresses, and boxes can easily fit in this unit. A 22-foot moving truck is ideal for filling this size of storage unit.