Tread And Riser Angles
I created a tread and riser angle chart to provide you with the angle of a stairway, using different treads and risers. For example, if you're going to use a 12 inch stair tread (this would be the depth of the stair step, not the width of the stairway) and a 5 1/2 inch riser (this would be the height of each step), the stairway would have a 24° angle. Stairs with larger angles are going to be harder to use than once with smaller angles.
Gray= Building Code Violations And Unsafe Stairs