How is the height of a stair riser measured?

The height of a stair riser is measured from the nosing of one tread to the nosing of the next tread. This measurement captures the vertical distance that a person must ascend when going from one step to the next and is crucial for ensuring consistent rise throughout a staircase, which impacts safety and comfort. When measuring this way, it accounts for any variations that might occur in tread depths, ensuring that the riser height is uniform, which is important for compliance with building codes and for providing a safe walking surface.

Measuring from the bottom of the tread to the top of the next tread would not provide an accurate riser height, as it could vary widely based on tread thickness. The measurement from the bottom of the stair to the top of the rail does not pertain to the riser itself but rather a different aspect of stair design. Finally, measuring from the floor to the first step does not align with how riser height is defined within the context of stair construction and design.