In a flight of stairs, what is the maximum difference allowed between the greatest and smallest riser heights?

The maximum allowable difference between the greatest and smallest riser heights in a flight of stairs is 3/8 of an inch. This requirement is established to ensure safety and accessibility, as varying riser heights can lead to tripping hazards and make navigating stairs more difficult, especially for individuals with mobility challenges. Consistency in riser height contributes to a smoother and more predictable transition between steps, reducing the risk of accidents.

Other options present larger tolerances, which may not align with safety standards. For example, a difference of 1/4 inch may be too lenient, while greater differences like 1/2 inch or 1 inch could significantly increase the risk of tripping. Therefore, the 3/8-inch maximum is the balance that emphasizes both safety and practical construction guidelines.