Free Online Stair Calculator
Calculate your staircase. See if it’s comfortable. Get the build plan.
Free staircase designer with live drawings and instant comfort checks. When the layout works, unlock exact measurements and a construction PDF — from $19.
No signup needed
Start designing immediately. No account or project setup before you know the stair fits.
Know before you build
Live comfort score tells you instantly if the stair will feel right to walk on.
Try before you buy
See the full layout free. Pay only when you’re ready to build.
From floor height to build plan in 5 minutes
Six steps between your tape measure and a plan you can review with your builder.
1. Enter your measurements
Floor height and available run — that’s all you need to start.
2. See live drawings
Side view, top view, and 3D update instantly as you adjust. No waiting.
3. Get a comfort verdict
Blondel formula + comfort grade tells you if the stair will feel natural to walk on.
4. Compare layouts
Straight, quarter-turn, half-turn — switch in one click and see what fits your space.
5. Refine before paying
Keep adjusting the layout for free until the plan is worth turning into build documents.
6. Unlock the build plan
Pay once, get exact dimensions, a cut-list starter, and a PDF packet to review with your builder.
Plan before you cut
Short guides for the decisions that stall stair projects — rise and run, headroom, layouts, and comfort.
Stair Calculations
How to Calculate Stair Rise and Run
A practical guide to calculating stair riser height, going, pitch, and total run before you build.
Comfort
Using the Blondel Formula for Comfortable Stairs
Learn what the Blondel formula means and how to use it to balance riser height and tread depth.
Planning
Stair Headroom: What to Check Before Building
How to think about stair headroom, floor openings, slab thickness, and common layout mistakes.
Made for real stair-planning decisions
Straight, quarter-turn, and half-turn layouts
Live drawings, comfort checks, headroom analysis, and shareable designs.
Your staircase measurements in 5 minutes
Enter floor height and run. Get drawings, a comfort check, and an exportable build plan. No signup required.