Stairs Calculators
Stair layout is geometry driven by one measurement — the total rise from finished floor to finished floor. The Stair Calculator turns that into a straight-run layout: the number of risers and treads, the exact riser height, the total run and the stringer length to buy, rounding to the riser count that lands closest to a comfortable 7 inches. The Spiral Staircase Calculator does the equivalent for a helical stair, where the tread is a wedge and depth is measured at a fixed walkline. The Spindle Spacing Calculator is the railing companion — it lays out evenly spaced balusters so the clear gap stays under the 4-inch limit for guards. Riser, tread and guard limits are shown from the IRC for reference; local amendments vary and the calculators don't enforce code.
3 calculators · all live