Straight stair geometry
Check geometric rise, going and pitch for a specified straight flight.
Quantity / scenario planning · Reviewed 7 October 2026Your inputs
Check all starting values against your project and product. Enter your own prices; keep costs on the same GST basis.
How to prepare your inputs
Use the actual material dimensions and a dimensioned plan. Allow for offcuts and distinguish nominal timber names from finished sizes.
How this calculation works
Riser = total rise ÷ risers. Treads = risers − 1 where the top floor forms the final landing. Run = treads × going. Pitch = atan(riser ÷ going).
2,700 mm across 15 risers gives 180 mm risers, 14 treads and a 3,500 mm run at 250 mm going.
Assumptions & exclusions
Geometry only: does not select compliant dimensions, design stringers, assess landings, headroom, handrails or nosings. Pitch describes the repeated step slope, not an overall landing-to-landing diagonal.
Your next step
Prepare a cutting list and check spans, grades, joints and fixings with the project designer.
Further reading
- Blocklayer geometric tool directory
These resources provide background information. Confirm current product specifications and project requirements with your supplier or trade professional.
What if my shape or product is different?
Use dimensions and product data that match the stated method. For complex work, calculate separate sections or obtain a project-specific take-off. Do not apply simple geometry to structural or compliance decisions.
Why are quantities rounded up?
Whole bags, packs, sheets or cartridges round up to purchasable units. Decimal area or volume results are planning figures; confirm order increments with the supplier.
Are my entries saved?
No. Entries remain in the current browser page and clear on reload. Printing can save your results and inputs as a PDF on your device.
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