What is the most popular storage unit size? Follow The 10x10 is one of the most common unit sizes because it is about the size of a small bedroom. Related articles How many storage units can you put on an acre? How much does it cost to build a mini-storage facility? What zoning do you need for a warehouse? Can I see the dimensions of my building on my land to scale? How much does a steel carport cost? Comments 0 comments Please sign in to leave a comment.