Stairs 3D: Framing Calculator

Build field-ready stair plans, inspect them in 3D, and export clean shop sheets — entirely offline, entirely on your device.

Stairs 3D is a professional stair framing calculator for carpenters, contractors, deck builders, and serious DIY builders. Enter your total rise and target step count, and the app instantly solves the geometry: rise per step, tread depth, stair angle, stringer length, stringer cut patterns, and a complete materials list. All in millimeters or imperial, whichever you prefer.


STAIR TYPES

• Straight Stair — Single-flight layout with live rise, run, and angle. Free.
• Stringer Layout — Board dimensions, cut geometry, and stringer count. Free.
• Landing Stair — Two-flight layout around a framed platform. Pro.
• L-Shaped & U-Shaped — Quarter-turn and return stairs with winder or landing options. Pro.
• Spiral Stair — Helical stair with radial treads, center column, and rotation direction. Pro.


WHAT YOU GET FOR EVERY STAIR

• Live calculation — every input updates the result instantly
• 3D visualization — orbit, inspect, and rotate a RealityKit model of your stair
• 2D blueprint — annotated plan and elevation views with dimensions
• Component inspector — tap any piece to see exact cut dimensions
• Material cut list — auto-generated quantities ready for take-off
• PDF export — printable blueprint for field, client, or shop use
• CSV export — machine-readable material list for spreadsheets or procurement


DESIGNED FOR THE JOB SITE

No account. No network. No subscriptions that lock your own files away. Projects and exports stay on this device unless you explicitly share them. If you cancel a plan, your projects remain yours — viewable, editable, and exportable.

Supports imperial (feet, inches, fractions) and metric (millimeters, centimeters). Configurable precision from whole numbers to four decimal places.


PRIVACY

Stairs 3D does not request camera, microphone, location, photo library, or tracking permissions. There are no analytics SDKs, no third-party data collection, and no advertising. The only external connection is the App Store for optional plan management.


FREE VS. PRO

Free includes straight stair calculation, stringer layout, 3D inspection, 2D blueprint, and project saving. Pro unlocks the landing, L-shaped, U-shaped, and spiral builders, plus PDF and CSV export.

Pro is