Stair stringer layout
Number of risers, riser height, tread run and stringer length from the total rise, checked against IRC limits.
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- Your own numbers, worked out as often as you like
- The full cut sheet you can print or save to My work
- 7 cited sources, linked, with the checks to make
- Every other tool for the same role, in the same plan
- A plain-words read of your result (a fuller AI read with the Bifrost AI add-on)
Included in these role plans
Example result · fictional numbers
What you get: cut sheet
Worked out by this tool from its default inputs. Its role plan lets you run your own numbers, print the sheet and save it.
14 risers at 7 11/16 in, 3 stringers from 16-ft stock
- Risers
- 14
- Riser height
- 7 11/16 in (7.714 in)
- Treads (runs)
- 13
- Total run
- 11 ft 4 1/2 in
- Stringer length (before trimming)
- 14 ft 6 1/16 in
- Stair angle
- 36.3°
Cut list
- Stringers
- 3 (max 18 in apart; yours are 18.0 in on center); the run is over 6 ft, so a 2x12 cut stringer needs a mid support
- Stringer stock
- 3 × 2x12 at 16 ft (14 ft 6 1/16 in each plus 6 in for the end cuts)
- Wood left after notching
- 5.03 in (5 in or more: fine)
- Bottom riser cut
- 6 3/16 in (7 11/16 in less the 1 1/2 in tread, so the first step matches)
- Top riser
- 7 11/16 in, plumb cut to the header
- Tread boards
- 13 at 36 in long, 11 1/2 in deep (includes a 1 in nosing)
and 2 more lines
Also on the sheet
- Square settings · 4 lines, starting with “Tongue (rise)”
The plain-words read of this example
A 9 ft 0 in rise needs 14 risers of 7 11/16 in each with 10 1/2 in treads, which passes the IRC limits of 7-3/4 in and 10 in. Order 3 × 2x12 at 16 ft (14 ft 6 1/16 in each plus 6 in for the end cuts), and expect 5.0 in of wood left behind each notch, which is enough. Cut the bottom riser 1 1/2 in short so the first step is the same height as the rest once the tread goes on. Set the gauges at 7 11/16 and 10 1/2 and step the square off the crowned edge; the common mistake is letting it drift between steps. Before you cut, check headroom (6 ft 8 in), nosing and the 3/8 in riser variation against your local code.
7 cited sources
- IRC 2021, R311.7 Stairways (International Code Council)
- Laying Out Basic Stair Stringers (Fine Homebuilding)
- How to Cut Stair Stringers (Fine Homebuilding)
- How to Build Stairs: a simple way to mark and cut stringers (Perkins Builder Brothers (YouTube))
- First Time Building Stairs: everything you need to know (Training Hands Academy (YouTube))
- Stairs and Handrails, 2021 IRC illustrated handout (City of Coeur d'Alene building department)
- Building safe and sturdy stairs for your deck (Simpson Strong-Tie blog)
Plus 7 step-by-step checks, a print layout and a link that reopens it with your numbers.