Stringer layout for a 84 inch rise
Calculate your stair rise with a total rise of 84 inches while adhering to the IRC riser limit of 7.75 inches. Ensure safety and compliance in your construction project.
Formula SSC-2026.1
IRC check pass
Risers / treads
11 / 10
Riser inside 4 to 7.75 in
Exact riser
7 5/8 in
194.0 mm
Total run
8 ft 9 in
2,667 mm
Stringer length
11 ft 2 7/16 in
Order 12 ft 2x12
Incline
38.66°
Square 7 5/8 in rise · 10 1/2 in run
Stringers @ 16 in
3
Throat 5.07 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 |
|---|---|---|---|---|---|---|
| 12 ft 2x12 | 11.84 ft cut | end cuts included | 3 boards | USD | $75.60 | Source Spec Material / Tool |
| Stringer delivery weight | 101 lb | — | 46 kg | 2.8 lb/ft planning weight | — | Source Spec Material / Tool |
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| Total rise | Risers | Exact riser | Treads | Run | 2x12 stock | Check |
|---|---|---|---|---|---|---|
| 7 ft 0 in | 11 | 7 5/8 in | 10 | 8 ft 9 in | 12 ft | Pass |
| 7 ft 6 in | 12 | 7 1/2 in | 11 | 9 ft 7 1/2 in | 14 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 84 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 a total rise of 84 inches, the maximum riser height allowed is 7.75 inches. This means you can have a maximum of 10 risers (84 inches ÷ 7.75 inches = 10.81, rounded down to 10).
It's important to note that headroom calculations are not included in this assessment, but should be considered separately for safety and comfort.
Code reference
IRC Section R311.7 - Stairways
Field questions
- What is the maximum riser height according to the IRC?
- The maximum riser height allowed by the IRC is 7.75 inches.
- How many risers can I have for a total rise of 84 inches?
- For a total rise of 84 inches, you can have a maximum of 10 risers.
- Is headroom included in the stair rise calculation?
- No, headroom is not calculated in the stair rise assessment and should be considered separately.