It's not one size fits all! The dimensions of your mudroom bench depend on the size of the room and the amount of storage space you would like. Ideally, your bench should have a height of 18 inches and a depth of 14 to 17 inches. As for the width, the most common dimensions are 35 to 48 inches, although this is largely based on the space in your mudroom and the structure you want to build.