StairCalculator is a dimension calculation tool for building structural steel and aluminum stairs. It provides imperial or metric dimensional calculations for steel stair stringers, including length, miter, and bevel cuts, running dimensions for tread holes in the web and running dimensions for handrail post holes in the flange. With a choice of three framing conditions at the top and bottom, bolted or welded treads, and stringer material from the AISC Shapes Database v15.0 November 2017 edition, StairCalculator can calculate dimensions for almost any stair stringer configuration. The calculator accepts negative dimensions for some inputs so you can move the stringer above or below the finished floor and above or below the nosing line giving StairCalculator the flexibility you need when drawing, checking, and fabricating steel and aluminum stairs.