Stringer layout for a 126 inch rise
Use our stair design calculator to determine total rise and ensure compliance with the IRC riser limit of 7.75 inches. Headroom calculations are not included.
Formula SSC-2026.1
IRC check pass
Risers / treads
17 / 16
Riser inside 4 to 7.75 in
Exact riser
7 7/16 in
188.3 mm
Total run
14 ft 0 in
4,267 mm
Stringer length
17 ft 6 in
Order 20 ft 2x12
Incline
36.87°
Square 7 7/16 in rise · 10 1/2 in run
Stringers @ 16 in
3
Throat 5.19 in on a 2x12
Rise, run, and the incline are scaled from the live riser and tread. Framing-square gauges match the exact riser and the tread depth.
| Item | Net | Waste | Order | Unit price | Line total | Source Spec Material / Tool |
|---|---|---|---|---|---|---|
| 20 ft 2x12 | 18.12 ft cut | end cuts included | 3 boards | USD | $126.00 | Source Spec Material / Tool |
| Stringer delivery weight | 168 lb | — | 76 kg | 2.8 lb/ft planning weight | — | Source Spec Material / Tool |
Source links open a product search on the Amazon storefront for the selected currency. SiteSpecCalc may earn a commission. The link does not change the quantities above.
| Total rise | Risers | Exact riser | Treads | Run | 2x12 stock | Check |
|---|---|---|---|---|---|---|
| 10 ft 6 in | 17 | 7 7/16 in | 16 | 14 ft 0 in | 20 ft | Pass |
| 11 ft 0 in | 18 | 7 5/16 in | 17 | 14 ft 10 1/2 in | 20 ft | Pass |
Show the deterministic formula
Risers = round(total rise ÷ target rise). Exact riser = total rise ÷ risers, reported to the nearest 1/16 in and in millimeters. Treads = risers − 1. Total run = treads × tread depth.
Diagonal = hypotenuse of stringer rise and total run. A dropped header uses total rise minus landing thickness. Stock is the next 8, 10, 12, 14, 16, 18, 20, or 24 ft board.
Stringers = floor(width ÷ 16) + 1, with a minimum of 2. Throat ≈ 11.25 − (riser × tread) ÷ hypotenuse.
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Project: Stringer layout for a 126 inch rise
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This sheet is an estimate for ordering and layout discussion. It is not a sealed design. Confirm the quantities with a licensed local professional and the authority having jurisdiction before you buy or build.
Engineering notes
When designing stairs, it's crucial to adhere to the International Residential Code (IRC) which specifies a maximum riser height of 7.75 inches. For a total rise of 126 inches, this means you would need to calculate the number of risers required to meet this limit.
Note that headroom is not calculated in this context, but it is an important consideration for overall stair safety and usability.
Code reference
IRC R311.7.5
Field questions
- What is the maximum riser height allowed by the IRC?
- The maximum riser height allowed by the IRC is 7.75 inches.
- How do I calculate the number of risers needed for a total rise of 126 inches?
- To calculate the number of risers, divide the total rise by the maximum riser height. For a total rise of 126 inches, you would divide by 7.75 inches, resulting in approximately 16.26 risers, which means you would need 17 risers to meet the height requirement.
- Is headroom included in the stair design calculations?
- No, headroom is not calculated in this context, but it is essential to ensure that there is adequate headroom for safe use of the stairs.