Free Online Stair Calculator
Free staircase designer with live drawings and instant comfort checks. When the layout works, unlock exact measurements and a construction PDF — from $19.
Design, share, and get feedback with just a link. No accounts, no project setup.
Live comfort score tells you instantly if the stair will feel right to walk on.
See the full layout free. Pay only when you’re ready to build.
Six steps between your tape measure and a construction-ready PDF.
Floor height and available run — that’s all you need to start.
Side view, top view, and 3D update instantly as you adjust. No waiting.
Blondel formula + comfort grade tells you if the stair will feel natural to walk on.
Straight, quarter-turn, half-turn — switch in one click and see what fits your space.
No accounts. Send the URL and the other person sees your exact design.
Pay once, get exact dimensions, a cut-list starter, and a construction PDF you can hand to your builder.
Short guides for the decisions that stall stair projects — rise and run, headroom, layouts, and comfort.
Stair Calculations
A practical guide to calculating stair riser height, going, pitch, and total run before you build.
Comfort
Learn what the Blondel formula means and how to use it to balance riser height and tread depth.
Planning
How to think about stair headroom, floor openings, slab thickness, and common layout mistakes.
Trusted by DIYers and professionals
2,400+ stair designs created
Built by a carpenter who got tired of spreadsheets.
Enter floor height and run. Get drawings, a comfort check, and an exportable build plan. No signup required.