2-Step Stair Stringer: Dimensions, Length & Cut Angle
Two-step stringers show up on low decks, back porches, and garage entries — anywhere the surface sits roughly a foot above grade. Every row is computed by the same engine as our interactive calculator.
2-step stringer dimensions · 10.5" tread
| Total Rise | Rise per Step | Total Run | Stringer Length | Cut Angle |
|---|---|---|---|---|
| 8" (0' 8") | 4.00" (4") | 10.5" | 13.2" (13 3/16") | 20.9° |
| 9" (0' 9") | 4.50" (4 1/2") | 10.5" | 13.8" (13 13/16") | 23.2° |
| 10" (0' 10") | 5.00" (5") | 10.5" | 14.5" (14 1/2") | 25.5° |
| 11" (0' 11") | 5.50" (5 1/2") | 10.5" | 15.2" (15 3/16") | 27.6° |
| 12" (1') | 6.00" (6") | 10.5" | 15.9" (15 15/16") | 29.7° |
| 13" (1' 1") | 6.50" (6 1/2") | 10.5" | 16.7" (16 11/16") | 31.8° |
| 14" (1' 2") | 7.00" (7") | 10.5" | 17.5" (17 1/2") | 33.7° |
| 15" (1' 3") | 7.50" (7 1/2") | 10.5" | 18.3" (18 5/16") | 35.5° |
Total run is fixed at 10.5" for 2 steps with a 10.5" tread: (steps − 1) × tread, because the upper floor or deck acts as the top step. For a different tread depth, total run = 1 × tread.
Rise per step is floored to the nearest 1/16" for framing-square layout. Different total rise? Use the interactive stringer calculator.
When do you need 2 steps?
Two-step stringers show up on low decks, back porches, and garage entries — anywhere the surface sits roughly a foot above grade.
A 2-step stringer covers total rises from 8" (0' 8") to 15" (1' 3") while keeping every riser at or under the IRC maximum of 7¾" (R311.7.5.1). Below 8", use a shorter stair; above 15", move to 3 steps.
What board do you need?
The longest stringer in the table is 18.3", so a 8-foot 2×12 covers every case with layout margin. Use solid, straight-grained 2×12 stock — after notching, the remaining "throat" must keep at least 3.5" of material for structural integrity.
Code checkpoints for a 2-step stair
- No handrail required by the IRC at 2 risers (the threshold is 4, per R311.7.8) — but many builders add one anyway, and local amendments can differ.
- Guards generally not required — the whole 2-step range stays at or under the 30" trigger (IRC R312.1.1), though landings and local rules can change that.
- Riser uniformity: the largest and smallest riser may differ by no more than 3/8" (IRC R311.7.5.1) — divide total rise by 2 and mark every notch from the same reference edge.
- Drop the bottom riser by one tread thickness so the first step matches the rest after treads go on.