Hallways should be between 3 and 6 feet wide
Comfortable coat removal requires between 3 and 5 feet of space. Note the number of guests you may have entering at any point in time, and plan your foyer and/or mudroom accordingly.
Stairways should be 39 to 48 inches wide.
Stair treads should be 10 to 11 inches deep with a maximum 7-inch rise to make them easy to traverse. There should be no more than 4 inches between treads in an open staircase.