How to use the Stair Calculator
Measure the floor-to-floor height and available plan space, then identify the stair use, jurisdiction, occupancy and any project criteria that the geometry study must be checked against.
The workspace starts blank. Load example temporarily fills the controls with demonstration data; reload or use the tool’s New or reset action, where provided, before entering live information.
- Choose the Jurisdiction / guidance context and Units, then enter Floor-to-Floor Height and any measured headroom.
- Enter maximum risers per flight, intermediate landing length and a clear Stair use / occupancy note.
- Set Preferred Rise, Going and Stair Width; compare the candidate riser counts and resulting pitch and plan run.
- Record the selected geometry and coordinate landings, headroom, structure, guarding, handrails, fire strategy and accessibility outside this calculation.
Worked examples
These examples explain the set-up, expected output and review needed without changing the tool workspace.
Straight stair in a constrained core
- Set-up
- Enter a 2,850 mm floor-to-floor height, the preferred rise and proposed going, then compare the generated integer riser options.
- Result
- Select a uniform riser count and see the corresponding actual rise, pitch and required horizontal run.
- Review
- Test the resulting stair and landing footprint against the current plan and section rather than selecting the closest preferred rise alone.
Two-flight coordination
- Set-up
- Enter the maximum risers per flight and intermediate landing length before reviewing the overall run.
- Result
- The geometry study identifies the flight split and landing allowance that require space in the core.
- Review
- Coordinate headroom over both flights, landing door conflicts and structural depth in a section.
Suggested workflow
Place the tool in a controlled project or practice process rather than treating its output as an isolated verdict.
- Establish use, regulatory context and available three-dimensional space.
- Choose a uniform geometry from integer riser options and test it in plan and section.
- Complete the separate life-safety, accessibility, guarding, handrail and structural reviews before issue.
Check before saving or issuing
- Floor-to-floor height comes from the coordinated level and finish build-up.
- The chosen option fits the available run including required landings.
- Recorded headroom, stair width and use criteria have been checked on the project geometry.
Common problems
- No practical option fits: do not force the preferred rise; revise the plan, flight arrangement or project criteria.
- Plan run seems too short: confirm the number of goings and include intermediate and end landings separately.
- Metric and imperial results differ: verify which units the entered dimensions used before switching display.
Output
A dimensioned stair geometry study with calculations and coordination warnings.
Professional boundary
This is a geometry check only; landings, headroom, guarding, handrails, accessibility, structure and fire safety require separate review.