2-1/4 inches is the most common width for hardwood flooring. Wider boards are becoming more and more popular, however; 5-inch boards are also a common choice.
Board width should be based on the style that you want for your room. Narrow boards are the classic wood floor look. Wider boards, on the other hand, can lend a contemporary or a rustic feeling, depending on the style of boards you choose. The size of the room is another factor. Commonly, people choose narrow boards for a small room, but that’s not always the right choice. Wider planks can make a small space appear larger, as there are fewer joints between the planks and the floor appears less crowded visually.