A 72" deck needs 10 risers at 7-3/16" and 9 treads: a 90" run on 10" treads, cut from 10 ft 2x12s with 5-7/16" of throat. Gentler: 11 risers at 6-9/16" on 11" treads, a 110" run (2R + T = 24.1").
finished to finished
fewest legal
nosing to nosing
3/4–1-1/4 under 11″
DCA 6 max 18
72" 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 12-5/16" 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 | 12-5/16" | 12.322" | 313 mm | |
| 2 | Tread 2 nose | 24-5/8"+ | 24.645" | 626 mm | |
| 3 | Tread 3 nose | 36-15/16"+ | 36.967" | 939 mm | |
| 4 | Tread 4 nose | 49-5/16"− | 49.289" | 1252 mm | |
| 5 | Tread 5 nose | 61-5/8" | 61.612" | 1565 mm | |
| 6 | Tread 6 nose | 73-15/16" | 73.934" | 1878 mm | |
| 7 | Tread 7 nose | 86-1/4" | 86.256" | 2191 mm | |
| 8 | Tread 8 nose | 98-9/16"+ | 98.579" | 2504 mm | |
| 9 | Top plumb cut | 110-7/8"+ | 110.901" | 2817 mm |
Then from mark 0 measure 6-3/16" down the bottom riser line and square across for the level heel cut.
Shortest run, steepest legal stair
Gentler climb, longer run
Sort any column, print a shop sheet, download CSV. Click a row to load it in the calculator.
| 0 | Bottom riser line | 0" | 0.000" | 0 mm | 0" |
|---|---|---|---|---|---|
| 1 | Tread 1 nose | 12-5/16" | 12.322" | 313 mm | 1' 5/16" |
| 2 | Tread 2 nose | 24-5/8"+ | 24.645" | 626 mm | 2' 5/8" |
| 3 | Tread 3 nose | 36-15/16"+ | 36.967" | 939 mm | 3' 15/16" |
| 4 | Tread 4 nose | 49-5/16"− | 49.289" | 1252 mm | 4' 1-5/16" |
| 5 | Tread 5 nose | 61-5/8" | 61.612" | 1565 mm | 5' 1-5/8" |
| 6 | Tread 6 nose | 73-15/16" | 73.934" | 1878 mm | 6' 1-15/16" |
| 7 | Tread 7 nose | 86-1/4" | 86.256" | 2191 mm | 7' 2-1/4" |
| 8 | Tread 8 nose | 98-9/16"+ | 98.579" | 2504 mm | 8' 2-9/16" |
| 9 | Top plumb cut | 110-7/8"+ | 110.901" | 2817 mm | 9' 2-7/8" |
Step-off 12-5/16" (12.3223") · bottom cut 6-3/16" under 1" treads · last mark 9' 2-7/8" at the top plumb cut.
| 0 | Bottom riser line | 0" | 0.000" | 0 mm | 0" |
|---|---|---|---|---|---|
| 1 | Tread 1 nose | 12-13/16" | 12.800" | 325 mm | 1' 13/16" |
| 2 | Tread 2 nose | 25-5/8"− | 25.600" | 650 mm | 2' 1-5/8" |
| 3 | Tread 3 nose | 38-3/8"+ | 38.400" | 975 mm | 3' 2-3/8" |
| 4 | Tread 4 nose | 51-3/16" | 51.200" | 1300 mm | 4' 3-3/16" |
| 5 | Tread 5 nose | 64" | 64.001" | 1626 mm | 5' 4" |
| 6 | Tread 6 nose | 76-13/16" | 76.801" | 1951 mm | 6' 4-13/16" |
| 7 | Tread 7 nose | 89-5/8"− | 89.601" | 2276 mm | 7' 5-5/8" |
| 8 | Tread 8 nose | 102-3/8"+ | 102.401" | 2601 mm | 8' 6-3/8" |
| 9 | Tread 9 nose | 115-3/16" | 115.201" | 2926 mm | 9' 7-3/16" |
| 10 | Top plumb cut | 128" | 128.001" | 3251 mm | 10' 8" |
Step-off 12-13/16" (12.8001") · bottom cut 5-9/16" under 1" treads · last mark 10' 8" at the top plumb cut.
05 / Field guide
This sheet works a 72" deck two ways. Option A uses the fewest risers the IRC allows, 10 at 7-3/16" on 10" treads. Option B adds one riser and uses 11" treads for a gentler 6-9/16" step. Both come with hook-once tape marks for the stringer edge, below the calculator.
72" ÷ 7.75 = 9.29, rounded up to 10 risers, each 7-3/16" (7.2000", 182.9 mm). On 9 treads of 10" the stair lands 90" (7' 6") out from the deck and climbs at 35.8°; 2R + T scores 24.40".
Each step is 12-5/16" along the stringer edge. Notches cut 5-13/16" deep, leaving 5-7/16" of throat in a 2x12; the cut length is 9' 6-1/2", so buy 10 ft stock.
One more riser drops each step to 6-9/16"− (6.5455"). With 11" treads the run grows to 110" (9' 2"), 20" more than Option A, and the angle eases to 30.8° with 2R + T at 24.09".
The diagonal is 12-13/16", the throat 5-5/8", and the stringer cut length 10' 10-13/16" (12 ft).
Take the tread thickness off the bottom riser: 7-3/16" becomes 6-3/16" under 1" 5/4 or composite treads, 5-11/16" under 1-1/2" 2x6 treads. Every finished step then measures 7-3/16".
At the top, the last tread notch sits 8-3/16" below the finished deck for 1" treads. Hung flush from the rim, the stringer edge meets the rim face 1" below the finished deck surface.
10 risers means a handrail is required (four or more risers), 34" to 38" above the nosings.
At 72" the open sides need a guard: 34" above the nosings, no opening wider than a 4-3/8" sphere, and the tread-riser triangle under 6".
The 90" 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.
Questions
10 risers at 7-3/16" with 9 treads, the fewest the IRC allows. For an easier climb, 11 risers at 6-9/16" with 10 treads.
About 9' 6-1/2" along the board for Option A, so 10 ft 2x12s; Option B needs 10' 10-13/16" (12 ft).
90" (7' 6") on 10" treads, or 110" (9' 2") on 11" treads with 11 risers. Leave a landing at least 36" deep beyond the last riser.
Yes. The total rise is 30" or more, so the open sides need a guard, and 10 risers also call for a handrail.
Not under AWC DCA 6, which asks for 2x12s. A 2x10 would keep only 3-7/16" of throat on Option A, under the 5" minimum.
Enter your exact rise in the calculator. 66" takes 9 risers and 78" takes 11; the riser count changes wherever the rise passes a multiple of 7-3/4".
Raised decks, basements and storeys