Stringer layout for a 114 inch rise
Learn about stair rise calculations, including the IRC limit of 7.75 inches for risers. Ensure your stair design meets safety standards.
Formula SSC-2026.1
IRC check pass
Risers / treads
15 / 14
Riser inside 4 to 7.75 in
Exact riser
7 5/8 in
193.0 mm
Total run
12 ft 3 in
3,734 mm
Stringer length
15 ft 6 in
Order 18 ft 2x12
Incline
37.79°
Square 7 5/8 in rise · 10 1/2 in run
Stringers @ 16 in
3
Throat 5.09 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 |
|---|---|---|---|---|---|---|
| 18 ft 2x12 | 16.14 ft cut | end cuts included | 3 boards | USD | $113.40 | Source Spec Material / Tool |
| Stringer delivery weight | 151 lb | — | 69 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 |
|---|---|---|---|---|---|---|
| 9 ft 6 in | 15 | 7 5/8 in | 14 | 12 ft 3 in | 18 ft | Pass |
| 10 ft 0 in | 16 | 7 1/2 in | 15 | 13 ft 1 1/2 in | 18 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 114 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) guidelines. For risers, the maximum height allowed is 7.75 inches. In your case, with a total rise of 114 inches, you will need to calculate the number of risers to ensure compliance with this limit.
Note that headroom calculations are not included in this assessment, but they are essential for overall safety and comfort in stair design.
Code reference
IRC 2018, Section R311.7
Field questions
- What is the maximum riser height according to the IRC?
- The maximum riser height according to the IRC is 7.75 inches.
- How do I calculate the number of risers needed for a total rise of 114 inches?
- To calculate the number of risers, divide the total rise (114 inches) by the maximum riser height (7.75 inches). This will give you the number of risers needed to comply with the IRC.
- Is headroom considered in the riser calculation?
- No, headroom is not calculated in the riser height assessment, but it is important for overall stair safety and comfort.