Stair Tangent Dark is a stair-building calculator designed to help rough-frame carpenters and occasional builders produce accurate stair layouts without redoing site measurements. The app converts a few input dimensions into complete layout data for straight, flared, circular and elliptical stairs, providing riser, tread and stringer information needed for on-site layout and construction.

Key Features

Stair Tangent Dark includes twelve dedicated stair calculators that cover locked and unlocked tread widths, number of risers and common stringer types. The app provides modules for 45° stringers, flared stringers and polygon winders, supports circular and elliptical stair geometry with an Ellipse Point Layout for X-Y plotting, and offers calculations for landing height, arc radius and the French winders technique. Entering a few dimensions returns the full set of layout values needed for on-site work, with typical circular layouts taking about 10 minutes and elliptical layouts often completed in about 30 minutes.

Advantages

The tool helps speed layout work and reduces cumulative calculation errors for builders who do not frame stairs every day, combining a broad set of stair types and techniques into a single utility so fewer separate tools are required. Ellipse Point Layout and X-Y plotting assist non-specialist carpenters in producing professional-grade layouts and clearer outputs aim to reduce rework and increase confidence in riser, tread and stringer measurements.

Disadvantages

Stair Tangent Dark is not intended to replace the judgment and experience of seasoned stairmakers who routinely perform these calculations by eye; very complex or unusual site-specific conditions may still require hands-on planning and adjustment beyond the calculator's results.