Stair Calculator, With the Stringer Layout Included

Field notes

The interface derives stair geometry from floor-to-floor height plus either a target riser height or a riser count, and from tread depth or available run. Its visible example turns a 108-inch rise into 15 risers and 14 treads, then reports a 147-inch run, 34.4-degree angle, and 182 7/16-inch stringer. Users can distinguish a floor-as-top-tread arrangement from an extra top tread and choose among several stair layouts.