Stair layout for a 96 inch rise
Calculate stair dimensions for a 96 inch total rise while adhering to IRC guidelines of 7.75 inch riser and 10 inch tread limits. Ensure compliance for safe and functional stairways.
Formula SSC-2026.1
IRC check pass
Risers / treads
13 / 12
Riser inside 4 to 7.75 in
Exact riser
7 3/8 in
187.6 mm
Total run
10 ft 6 in
3,200 mm
Stringer length
13 ft 2 3/8 in
Order 14 ft 2x12
Incline
37.30°
Square 7 3/8 in rise · 10 1/2 in run
Stringers @ 16 in
3
Throat 5.21 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 |
|---|---|---|---|---|---|---|
| 14 ft 2x12 | 13.82 ft cut | end cuts included | 3 boards | USD | $88.20 | Source Spec Material / Tool |
| Stringer delivery weight | 118 lb | — | 53 kg | 2.8 lb/ft planning weight | — | Source Spec Material / Tool |
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| Target | Risers | Exact riser | Run | Angle | Check |
|---|---|---|---|---|---|
| 7 in | 14 | 6 7/8 in | 11 ft 4 1/2 in | 35.1° | Pass |
| 7 1/2 in | 13 | 7 3/8 in | 10 ft 6 in | 37.3° | Pass |
| 7 3/4 in | 12 | 8 in | 9 ft 7 1/2 in | 39.7° | Warning |
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: Stair layout for a 96 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 with a total rise of 96 inches, it is essential to adhere to the International Residential Code (IRC) guidelines. The maximum riser height allowed is 7.75 inches, and the minimum tread depth is 10 inches. This ensures safety and comfort for users.
Headroom is not calculated in this design, but it is crucial to ensure that there is adequate clearance above the stairs for safe passage.
Code reference
IRC guidelines for stair design
Field questions
- What is the maximum riser height allowed by the IRC?
- The maximum riser height allowed by the IRC is 7.75 inches.
- What is the minimum tread depth required for stairs?
- The minimum tread depth required for stairs is 10 inches according to IRC guidelines.
- Is headroom included in the stair design calculations?
- No, headroom is not calculated in the stair design, but it is important to ensure adequate clearance above the stairs.