Stairs for an 8 ft (96 in) total rise
An 8 ft (96 in) total rise needs 13 risers of 7-3/8 inches and 12 treads. With 10 inch treads the total run is 120 inches (10 ft) and each stringer is about 153-11/16 inches (12 ft 9-11/16 in) along the slope.
How to work it out
- 96 in ÷ 7.75 in max = 12.39 → round up to 13 risers, each 96 in ÷ 13 = 7-3/8 in strong (7.38 in)
- 12 treads × 10 in = 120 in run · √(96² + 120²) = 153-11/16 in along the slope
- Comfort check: 2 × 7-3/8 in + 10 in = 24.8 in (24–26 in is comfortable) · stair angle 36.4 degrees
- Throat: 11-1/4 in board − 5.94 in notch depth = 5-5/16 in
- Tread board: 10 in tread + 3/4 in nosing + 0 in riser board = 10-3/4 in
- Top level cut: 7-3/8 in riser + 1 in tread − 0 in top finish = 8-3/8 in below the upper subfloor
An exact 8 ft rise is typical of basement stairs and lofts. Between floors of a house, the total rise includes the floor framing, so an 8 ft ceiling usually means a rise closer to 105–110 in — measure yours from finished floor to finished floor.
Adjust for your project
More options: Max riser · Spacing · Stringer board …
- Steps to cut
- 12 steps to cut in each stringer + the upper floor is the top step
- Total run (how far the stairs reach out)
- 120 in (10 ft)
- Stringer length (along the slope)
- 153-11/16 in (12 ft 9-11/16 in)
- Stringers needed
- 4 stringers
- Stringer stock to buy
- 4 × 2×12 × 14 ft
- Tread board depth to buy (tread + nosing + riser board)
- 10-3/4 in
- Drop the stringer (trim off the bottom)
- 1 in
- Top level cut, measured down from the top surface
- 8-3/8 in
- Wood left below the notches (throat)
- 5-5/16 in
| Item | What to buy | Notes |
|---|---|---|
| Stringers | 4 × 2×12 × 14 ft | Straight boards with no big knots along the bottom edge, where the wood is in tension. |
| Treads | 12 treads, each 36 in long × 10-3/4 in deep | Depth = tread + nosing + riser board. |
| Hardware | Hangers or a hanger board at the top, fastened to the header or rim; screws for the treads and risers | Plus a handrail on at least one side — four or more risers (2021 IRC R311.7.8). |
Where to mark each step (height above the bottom)
| Step | Height above the bottom | Guard on open sides? |
|---|---|---|
| Tread 1 | 7-3/8 in | — |
| Tread 2 | 14-3/4 in | — |
| Tread 3 | 22-1/8 in | — |
| Tread 4 | 29-9/16 in | — |
| Tread 5 | 36-15/16 in | Yes — over 30 in |
| Tread 6 | 44-5/16 in | Yes — over 30 in |
| Tread 7 | 51-11/16 in | Yes — over 30 in |
| Tread 8 | 59-1/16 in | Yes — over 30 in |
| Tread 9 | 66-7/16 in | Yes — over 30 in |
| Tread 10 | 73-7/8 in | Yes — over 30 in |
| Tread 11 | 81-1/4 in | Yes — over 30 in |
| Tread 12 | 88-5/8 in | Yes — over 30 in |
| Upper floor | 96 in | Yes — over 30 in |
One step fewer or more
| Risers | Each step | Treads | Tread depth | Total run | Check |
|---|---|---|---|---|---|
| 12 risers | 8 in | 11 | 10 in | 110 in | Risers too tall |
| 13 risers (shown) | 7-3/8 in | 12 | 10 in | 120 in | OK |
| 14 risers | 6-7/8 in | 13 | 10 in | 130 in | OK |
- Each step is marked to the nearest 1/16 in. Stepping off 7-3/8 in 13 times would put the top 1/8 in low, so mark each step from the Where to mark each step table below instead.
- Stair guard required from tread 5: it sits more than 30 in above the bottom, so open sides need a guard at least 34 in high (IRC R312.1.1, R312.1.2). This assumes the floor beside the stair is level with the bottom landing — measure where it falls away.
- Headroom: keep at least 6 ft 8 in clear above the line of the nosings along the whole flight (IRC R311.7.2). Enter the upper floor thickness to get the shortest ceiling opening.
- Leave a landing at the bottom (and the top, unless it is the floor itself) at least 36 in deep and as wide as the stair (IRC R311.7.6).
- Trim 1 in off the bottom of each stringer (one tread thickness) so the first step comes out the same 7-3/8 in as the rest.
Run and stringer for a 96 in rise, by tread depth
| Tread depth | Total run (how far the stairs reach out) | Stringer length (along the slope) | Stringer stock to buy |
|---|---|---|---|
| 10 in | 120 in (10 ft) | 153-11/16 in (12 ft 9-11/16 in) | 4 × 2×12 × 14 ft |
| 10.5 in | 126 in (10 ft 6 in) | 158-3/8 in (13 ft 2-3/8 in) | 4 × 2×12 × 16 ft |
| 11 in | 132 in (11 ft) | 163-3/16 in (13 ft 7-3/16 in) | 4 × 2×12 × 16 ft |
| 11.5 in | 138 in (11 ft 6 in) | 168-1/8 in (14 ft 1/8 in) | 4 × 2×12 × 16 ft |
| 12 in | 144 in (12 ft) | 173-1/16 in (14 ft 5-1/16 in) | 4 × 2×12 × 16 ft |
What to know about stairs for an 8 ft rise
At 96 in the flight is well inside the 12 ft 7 in (151 in) limit on the rise of a single flight in IRC R311.7.3, so no mid-flight landing is required. Thirteen risers of about 7-3/8 in sit under the 7¾ in maximum with roughly ⅜ in to spare, and the 10 in treads are exactly the R311.7.5.2 minimum. That means every tread needs a nosing of ¾ to 1¼ in (R311.7.5.3) — the exception only applies at 11 in or deeper. Headroom must be at least 6 ft 8 in over the whole flight (R311.7.2), which is often the tight spot under a basement doorway or beam.
The run is 120 in, a full 10 ft of floor from the bottom riser to the top one, plus room to step on and off. Many basement openings are shorter than that. Taller risers can’t help much because you are already near the limit, so the usual fixes are a landing and a turn, or winders designed to code.
Each stringer is about 12.8 ft along the slope, so the stock line asks for 14 ft 2×12s. The throat is 5.31 in. A long cut stringer also flexes: indoors it usually bears on the floor at the bottom, hangs from the header or rim at the top, and is fastened to a wall or blocking along one side. Deck guides such as DCA 6 limit how far a cut stringer may span without support, so check yours if this flight is outdoors.
One foot more: Stair stringers for a 9 ft rise is right at the riser limit. Two feet more: Stair stringers for a 10 ft rise. For a deck-height flight, see How many steps for a 4 ft deck.
Different size? Use the full Stair Stringer Calculator.
What you’ll need
- Framing squareBudget price
The tool for laying out stair stringers and rafters: rise on one leg, run on the other.
See options on Amazon (opens in a new tab) - Stair gaugesBudget price
Small brass or steel buttons that clamp to a framing square so every rise and run you mark is identical.
See options on Amazon (opens in a new tab) - Circular saw (7¼ in)Mid-range price
The most versatile first power saw: crosscuts framing lumber, rips boards and, with a straightedge, breaks down plywood sheets.
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Frequently asked questions
How long is the stringer for an 8 ft rise with 11 in treads?
About 163-3/16 inches (13 ft 7-3/16 in), with 132 inches (11 ft) of run — 4 × 2×12 × 16 ft. Eleven-inch treads need no nosing under R311.7.5.3, but the flight takes an extra foot of floor.
How many risers for 96 in with a 7 in maximum riser?
14 risers of 6-7/8 inches and 13 treads, for 130 inches (10 ft 10 in) of run at 10 inch treads. Lower risers are easier on knees but add a tread and 10 inches to the footprint.
Other common sizes
- How many steps for a 3 ft deck — 5 risers
- How many steps for a 2 ft deck — 4 risers
- How many steps for a 30 in deck — 4 risers
- How many steps for a 4 ft deck — 7 risers
- Stair stringers for a 2.7 m rise — 15 risers
Sources
- International Code Council, 2021 International Residential Code, Chapter 3 Building Planning (opens in a new tab) — R311.7.1 width (36 in), R311.7.2 headroom (6 ft 8 in), R311.7.3 vertical rise of a flight (12 ft 7 in), R311.7.5.1 risers (7¾ in; open risers more than 30 in up must not pass a 4 in sphere), R311.7.5.2 treads (10 in), R311.7.5.3 nosings (¾–1¼ in unless the tread is 11 in or deeper), R311.7.6 landings (36 in deep), R311.7.8 handrails, R312.1 guards.
- American Wood Council, DCA 6 Prescriptive Residential Wood Deck Construction Guide (2015 IRC edition) (opens in a new tab) — Stair requirements, Figures 28, 29, 31 and 34: 2×12 minimum stringers; cut stringers span no more than 6 ft 0 in and keep at least 5 in below the notches; at least three cut stringers at no more than 18 in on center; sloped hangers or a hanger board at the top; an intermediate landing where the total rise exceeds 12 ft; stringers bear on footings below frost depth, not on pads or patios that aren’t founded that deep.