Plan a stair
Every trade, one set of measurements
Stair planner
A stair is the one thing here with no plan shape at all: it is two figures between two levels. The total rise decides the number of risers and therefore their height; the width decides the stringers and what has to be held. From those come the flight's own geometry, the stringer length, the handrail run and the spacing of the guardrail posts.
- 1 Measure the stair
- 2 Choose its finishes
- 3 Save it to My Project
Give the stair a rise and a width, and it is drawn here with every figure beside it.
The stair
Nothing here is required. Each figure appears as soon as it has what it needs.
The total rise — floor level to floor level, not tread to tread — and the width of the flight. Everything else on the page is worked from those two.
Add a stair
The rise between the two levels and the width it is built to, which is all a flight is. How many risers, how high each one is and how far it runs follow from a target riser and the code, and are worked out rather than measured.
Everything the stair needs
In the order the work is done. No row has a figure yet.
Nothing in this stair is everything the stair needs yet. Choose how a surface is finished, or what else is being done, and its rows appear here.
Assumptions assumed
Everything the figures above rest on that you did not give, and what they are still waiting for.
Nothing is assumed yet: give the stair its measurements to begin.
How the planner runs
- Give the flight its total rise, measured between finished floor levels, and its width.
- Read the riser count and height that fall out of it, and check them against the limits your code sets.
- Take the stringer length for the going the risers produce.
- Add the handrail along the flight and the guardrail posts at the spacing it allows.
- Save it into your project with the rest of the job.
Where the figures come from
- Stair Rise & Run Calculator
- Spiral Stair Helix Geometry Calculator
- Structural Steel Stair Stringer Length Calculator
- Handrail Length Calculator
- Highway Guardrail Post Spacing Calculator
Reading for the decisions
Questions
- Why is the rise measured between finished floors?
- Because the stair has to arrive at the finished floor, not at the subfloor. A screed or a floor covering added after a flight was set out is the classic way a top riser ends up a different height from the rest, which is exactly what every code's uniformity rule forbids.
- Does it check the riser height against the code?
- It gives the riser height the rise produces and names the limits it sits against; what a particular jurisdiction allows is a matter for that jurisdiction. The site's own stair checker takes risers as BUILT and measures the spread between them, which is a different question and the one that matters on an existing flight.
- Why is the going not asked for?
- The going follows from the risers once the rise is divided, and asking for both invites a pair that do not agree. If your going is fixed by the space you have, set the riser count to suit it and read the rise back.
- Is the balustrade infill counted?
- The posts are, at the spacing the guardrail calculator allows. What fills between them — glass, spindles, wire — is a choice with its own quantity, and the site's baluster and cable calculators take the run this page gives them.
When the work is a job rather than a room. Plenty of it never starts from a space — a slab, a roof, a deck, a panel upgrade. Each of those is a job takeoff: give it the few figures that job is described by, and every trade in it comes back together, the way the room does here.