How to Calculate Stair Rise and Run

Measure the finished floor-to-finished floor height. This is the total rise, and every riser must divide that height evenly enough to keep the staircase comfortable.

For a typical residential stair, divide the total rise by a target riser height around 170 to 185 mm, then round to a whole number of risers.

The going is the horizontal walking depth from one nosing to the next. Once you know the riser count, choose a going that fits the available run and still feels natural underfoot.

A stair with shallow going may feel steep even when the riser height looks acceptable, so rise and run should always be checked together.

Pitch angle is the slope of the stair. Most everyday stairs feel comfortable around the low-to-mid 30 degree range, while steeper stairs become harder to use regularly.

Use the editor to test several step counts quickly. Small changes can improve comfort without changing the stairwell dramatically.