Riser tool
Stair geometry tool in Riser
One floor-to-floor measurement in, a whole flight out: equal risers, going, total run, pitch, diagonal cut line and code checks, saved to the project the runner quote comes from.
Stair geometry is the layer underneath every runner job. Get the riser count and going right and the tread depth, nosing and step count that drive the runner length fall out of it. The geometry tool inside Riser takes the total rise between finished floors, a target riser height and the going you want, then returns the equal riser height, tread count, total run, pitch angle and the diagonal cut line, with a live section diagram that redraws as you type.
What it works out
- Riser count rounded to a whole number, then the exact equal riser height.
- Tread going, total run and the floor opening the flight needs.
- Pitch angle and the stringer diagonal for the cut line.
- The 2R+G comfort check, plus IRC and UK Approved Document K limits either side.
- Headroom and landing warnings when the flight is too steep or too long.
Why it lives in the workspace
On site you rarely calculate one flight in isolation. A staircase has a main flight, a half-landing and often a winder set, and each of those needs its own geometry before you can price the soft finish. In Riser each flight is saved against the staircase record, so the quote, cut list, visual and job all read from the same numbers rather than a photo of a notepad. Change the going after a site visit and everything downstream updates with it.
Free versions of the same maths
Every calculation here is also available free and open on this site with no sign-in. Use the stair calculator (rise & run) for a full flight, the stair layout calculator for the floor opening and headroom, and the stair runner calculator when the flight is set and you need the runner length. For a full staircase with landings, the stair runner length calculator adds nosings, winders and pattern repeat waste.
Frequently asked questions
What does the stair geometry tool in Riser do?
You enter the floor-to-floor rise, a target riser height and your going, and it returns the riser count, the exact equal riser height, tread going, total run, pitch angle and the diagonal cut line, with a live section diagram. It then checks the result against IRC and UK Approved Document K limits and the 2R+G comfort rule, and saves the flight to a project so the runner quote is built from the same numbers.
How is it different from the free stair calculators on this site?
The free calculators on stairrunnercalculator.com give you the same maths with no sign-in. The Riser version adds the workspace layer: saved flights per staircase, presets for the geometry you build most often, client-ready PDF exports with your logo, and the ability to push a flight straight into a quote, cut list and job.
Do I need a Riser account to use it?
Only for the saved and client-facing version. Every geometry calculation itself stays free and open on this website, and a Riser account is free to create if you want the project, quoting and portal side.
Does it check building regulations?
It flags the common limits — maximum riser, minimum going, maximum pitch and the 2R+G comfort band — for both IRC residential stairs and UK private stairs. It is a design aid, not a substitute for your local building control officer signing the flight off.