A 114" floor-to-floor stair needs 15 risers at 7-5/8" and 14 treads: a 140" run on 10" treads, cut from 16 ft 2x12s with 5-3/16" of throat. Gentler: 16 risers at 7-1/8" on 11" treads, a 165" run (2R + T = 25.3").
finished to finished
fewest legal
nosing to nosing
3/4–1-1/4 under 11″
DCA 6 max 18
114" total rise
Hook the tape once at mark 0, where the bottom riser line meets the top edge of the 2x12, and pencil every mark from that same hook. Each step is 12-9/16" along the edge; marks are rounded once each, so nothing drifts.
| Done | # | Mark | Tape | Decimal | mm |
|---|---|---|---|---|---|
| 0 | Bottom riser line | 0" | 0.000" | 0 mm | |
| 1 | Tread 1 nose | 12-9/16" | 12.560" | 319 mm | |
| 2 | Tread 2 nose | 25-1/8" | 25.121" | 638 mm | |
| 3 | Tread 3 nose | 37-11/16" | 37.681" | 957 mm | |
| 4 | Tread 4 nose | 50-1/4" | 50.241" | 1276 mm | |
| 5 | Tread 5 nose | 62-13/16" | 62.801" | 1595 mm | |
| 6 | Tread 6 nose | 75-3/8" | 75.362" | 1914 mm | |
| 7 | Tread 7 nose | 87-15/16"− | 87.922" | 2233 mm | |
| 8 | Tread 8 nose | 100-1/2"− | 100.482" | 2552 mm | |
| 9 | Tread 9 nose | 113-1/16"− | 113.042" | 2871 mm | |
| 10 | Tread 10 nose | 125-5/8"− | 125.603" | 3190 mm | |
| 11 | Tread 11 nose | 138-3/16"− | 138.163" | 3509 mm | |
| 12 | Tread 12 nose | 150-3/4"− | 150.723" | 3828 mm | |
| 13 | Tread 13 nose | 163-5/16"− | 163.283" | 4147 mm | |
| 14 | Top plumb cut | 175-13/16"+ | 175.844" | 4466 mm |
Then from mark 0 measure 6-9/16" down the bottom riser line and square across for the level heel cut.
Shortest run, steepest legal stair
Gentler climb, longer run
Floor to floor = ceiling + joists + subfloor. With 12-1/2" of floor framing and ceiling, the stairwell opening over Option A starts 18-5/16" from the bottom riser and runs 10' 1-11/16" for 6'-8" of headroom.
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| 0 | Bottom riser line | 0" | 0.000" | 0 mm | 0" |
|---|---|---|---|---|---|
| 1 | Tread 1 nose | 12-9/16" | 12.560" | 319 mm | 1' 9/16" |
| 2 | Tread 2 nose | 25-1/8" | 25.121" | 638 mm | 2' 1-1/8" |
| 3 | Tread 3 nose | 37-11/16" | 37.681" | 957 mm | 3' 1-11/16" |
| 4 | Tread 4 nose | 50-1/4" | 50.241" | 1276 mm | 4' 2-1/4" |
| 5 | Tread 5 nose | 62-13/16" | 62.801" | 1595 mm | 5' 2-13/16" |
| 6 | Tread 6 nose | 75-3/8" | 75.362" | 1914 mm | 6' 3-3/8" |
| 7 | Tread 7 nose | 87-15/16"− | 87.922" | 2233 mm | 7' 3-15/16" |
| 8 | Tread 8 nose | 100-1/2"− | 100.482" | 2552 mm | 8' 4-1/2" |
| 9 | Tread 9 nose | 113-1/16"− | 113.042" | 2871 mm | 9' 5-1/16" |
| 10 | Tread 10 nose | 125-5/8"− | 125.603" | 3190 mm | 10' 5-5/8" |
| 11 | Tread 11 nose | 138-3/16"− | 138.163" | 3509 mm | 11' 6-3/16" |
| 12 | Tread 12 nose | 150-3/4"− | 150.723" | 3828 mm | 12' 6-3/4" |
| 13 | Tread 13 nose | 163-5/16"− | 163.283" | 4147 mm | 13' 7-5/16" |
| 14 | Top plumb cut | 175-13/16"+ | 175.844" | 4466 mm | 14' 7-13/16" |
Step-off 12-9/16" (12.5603") · bottom cut 6-5/8" under 1" treads · last mark 14' 7-13/16" at the top plumb cut.
| 0 | Bottom riser line | 0" | 0.000" | 0 mm | 0" |
|---|---|---|---|---|---|
| 1 | Tread 1 nose | 13-1/8"− | 13.106" | 333 mm | 1' 1-1/8" |
| 2 | Tread 2 nose | 26-3/16"+ | 26.212" | 666 mm | 2' 2-3/16" |
| 3 | Tread 3 nose | 39-5/16" | 39.318" | 999 mm | 3' 3-5/16" |
| 4 | Tread 4 nose | 52-7/16" | 52.424" | 1332 mm | 4' 4-7/16" |
| 5 | Tread 5 nose | 65-1/2"+ | 65.530" | 1664 mm | 5' 5-1/2" |
| 6 | Tread 6 nose | 78-5/8" | 78.636" | 1997 mm | 6' 6-5/8" |
| 7 | Tread 7 nose | 91-3/4" | 91.742" | 2330 mm | 7' 7-3/4" |
| 8 | Tread 8 nose | 104-7/8"− | 104.848" | 2663 mm | 8' 8-7/8" |
| 9 | Tread 9 nose | 117-15/16"+ | 117.953" | 2996 mm | 9' 9-15/16" |
| 10 | Tread 10 nose | 131-1/16" | 131.059" | 3329 mm | 10' 11-1/16" |
| 11 | Tread 11 nose | 144-3/16"− | 144.165" | 3662 mm | 12' 3/16" |
| 12 | Tread 12 nose | 157-1/4"+ | 157.271" | 3995 mm | 13' 1-1/4" |
| 13 | Tread 13 nose | 170-3/8" | 170.377" | 4328 mm | 14' 2-3/8" |
| 14 | Tread 14 nose | 183-1/2"− | 183.483" | 4660 mm | 15' 3-1/2" |
| 15 | Top plumb cut | 196-9/16"+ | 196.589" | 4993 mm | 16' 4-9/16" |
Step-off 13-1/8"− (13.1059") · bottom cut 6-1/8" under 1" treads · last mark 16' 4-9/16" at the top plumb cut.
05 / Field guide
This sheet works a 114" floor-to-floor rise two ways. Option A uses the fewest risers the IRC allows, 15 at 7-5/8" on 10" treads. Option B adds one riser and uses 11" treads for a gentler 7-1/8" step. Both come with hook-once tape marks for the stringer edge, below the calculator.
114" ÷ 7.75 = 14.71, rounded up to 15 risers, each 7-5/8"− (7.6000", 193.0 mm). On 14 treads of 10" the stair lands 140" (11' 8") out from the upper floor edge and climbs at 37.2°; 2R + T scores 25.20".
Each step is 12-9/16" along the stringer edge. Notches cut 6-1/16" deep, leaving 5-3/16" of throat in a 2x12; the cut length is 14' 11-13/16", so buy 16 ft stock.
One more riser drops each step to 7-1/8" (7.1250"). With 11" treads the run grows to 165" (13' 9"), 25" more than Option A, and the angle eases to 32.9° with 2R + T at 25.25".
The diagonal is 13-1/8"−, the throat 5-1/4", and the stringer cut length 16' 7-15/16" (18 ft).
Take the tread thickness off the bottom riser: 7-5/8" becomes 6-5/8" under 1" 5/4 or composite treads, 6-1/8" under 1-1/2" 2x6 treads and 6-9/16" under 1-1/16" oak treads. Every finished step then measures 7-5/8".
At the top, the last tread notch sits 8-5/8" below the finished floor for 1" treads. Seated on a 2x header, the header top goes 16-5/16" below the finished floor with oak treads.
15 risers means a handrail is required (four or more risers), 34" to 38" above the nosings.
The 140" run is more than the 6'-0" a cut stringer may span under DCA 6: set 1 4x4 support post on 12" footings under the stringers, or build a landing.
The IRC wants 6'-8" measured plumb from the nosing line. With 12-1/2" of floor framing and ceiling, the opening above Option A must start 18-5/16" out from the bottom riser and run 121-11/16" (10' 1-11/16") to the top of the stair.
Floor to floor is the ceiling height plus the joists and subfloor: 114" is a 102" ceiling over 2x12 joists, or 104" over 2x10s.
Questions
15 risers at 7-5/8" with 14 treads, the fewest the IRC allows. For an easier climb, 16 risers at 7-1/8" with 15 treads.
About 14' 11-13/16" along the board for Option A, so 16 ft 2x12s; Option B needs 16' 7-15/16" (18 ft).
140" (11' 8") on 10" treads, or 165" (13' 9") on 11" treads with 16 risers. Leave a landing at least 36" deep beyond the last riser.
A 102" ceiling over 2x12 joists and a 3/4" subfloor, or 104" over 2x10s.
Not under AWC DCA 6, which asks for 2x12s. A 2x10 would keep only 3-3/16" of throat on Option A, under the 5" minimum.
Enter your exact rise in the calculator. 108" takes 14 risers and 120" takes 16; the riser count changes wherever the rise passes a multiple of 7-3/4".
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