Which leg is which
The body (or blade) is the long leg, 24" by 2" on a standard steel square. The tongue is the short leg, 16" by 1-1/2". For stairs the unit rise goes on the tongue and the unit run on the body, both read on the outside edges.
Framing square stair gauge guide & 1:1 templates
Framing square stair gauge guide: clamp the stair gauges at the unit rise on the tongue and the unit run on the body, trace, then step along the board. For 7-3/16" × 10" the line climbs at 35.8° with a 12-5/16" step-off. Print the 1:1 notch template, the angle protractor and the shop checklists at 100%.
Drawing the layout…
in
× 5 risers = 36"
in
- 1 · Clamp a gauge at 7-3/16" on the outside of the tongue (16" leg).
- 2 · Clamp the other at 10" on the outside of the body (24" leg).
- 3 · Hold both gauges against the board's crown edge; trace both legs.
- 4 · Slide to the next mark on your tape (Running Tape Marks), not to the last line.
- 5 · Circular saw: stop ¼" short of each inside corner; finish with a hand or jig saw.
- 6 · Cut one stringer, test it on site, then trace it for the rest.
Framing square · stair gauges
7-3/16" on the tongue,
10" on the body
Step-off along the edge
12-5/16"
12.322" · 313 mm
Stair angle
35.8°
54.2° plumb-cut bevel off square
Bottom riser cut
6-3/16"
7-3/16" − 1" tread
Stringer board
8 ft
4 × 2x12, cut 4' 4-15/16"
- Max riser 7-3/4"IRC R311.7.5.1
- Min tread 10"IRC R311.7.5.2
- Blondel 2R + T = 24"–26"Comfort rule
- Stringer throat ≥ 5"AWC DCA 6 Fig. 28
- Cut stringer span ≤ 6'-0"AWC DCA 6 Fig. 28
Layout
- Total rise
- 36"36.000" · 914 mm
- Risers
- 57-3/16" each (7.2000")
- Treads
- 410" unit run + 1" nosing
- Total run
- 40"3' 4" · 1016 mm
- Stair angle
- 35.8°2R + T = 24.40"
- Step-off (diagonal)
- 12-5/16"12.3223"
Cutting
- Framing square
- 7-3/16" tongue · 10" bodyClamp stair gauges on the outside edge
- Bottom riser (heel)
- 6-3/16"Full riser less 1" for 5/4 wood treads
- Notch depth
- 5-13/16"Inside corner, square to the edge
- Throat left
- 5-7/16"2x12: meets the 5" DCA 6 minimum
- Stringer edge below deck
- 1"Flush: hung from the rim with sloped hangers
- Top tread notch below deck
- 8-3/16"One riser plus one tread thickness
- Stringers
- 4 × 2x1211-1/2" on centre across 36"
- Board length
- 8 ftCut length 4' 4-15/16" along the board
Code checklist
- Max riser 7-3/4"IRC R311.7.5.1
7-3/16" · Every riser, including the first, finishes at the same height.
- Min tread 10"IRC R311.7.5.2
10" · Measured nosing to nosing, horizontally.
- Blondel 2R + T = 24"–26"Comfort rule
24.40" · Inside the comfortable band most people climb without thinking.
- Nosing 3/4"–1-1/4"IRC R311.7.5.3
1" · Required on closed risers where the tread is under 11". Open risers are exempt.
- Stringer throat ≥ 5"AWC DCA 6 Fig. 28
5-7/16" · Uncut wood left under each notch of the 2x12.
- Cut stringer span ≤ 6'-0"AWC DCA 6 Fig. 28
40" · Within the prescriptive horizontal span.
- Stringer spacingAWC DCA 6 Fig. 29
11-1/2" o.c. · 2x or 5/4 treads may span 18" at most between cut stringers.
- Stringer stock 2x12 minAWC DCA 6
2x12 · Prescriptive minimum for deck stair stringers.
- Stair width ≥ 36"IRC R311.7.1
36" · Clear width above the handrail height.
- Single flightIRC R311.7.3
36" · Under the 151" limit for one flight.
- Handrail requiredIRC R311.7.8
5 risers · Four or more risers: graspable handrail 34"–38" above the nosing line, on at least one side.
- Stair guard requiredIRC R312.1.1
36" · Open sides need a guard: 34" above the nosings, 4-3/8" sphere rule.
IRC 2021 section numbers; the 2024 IRC keeps these limits and renumbers the stair sections to R318. Your local code and inspector govern.
Framing square chart 18 rows
Sort any column, print a shop sheet, download CSV. Click a row to load it in the calculator.
| 10" | 31.0° | 11-11/16"− · 11.662" | 5-1/8" | 6-1/8" | 22.00" | ||
| 10-1/2" | 29.7° | 12-1/16"+ · 12.093" | 5-3/16" | 6-1/16" | 22.50" | ||
| 11" | 28.6° | 12-1/2"+ · 12.530" | 5-1/4" | 6" | 23.00" | ||
| 10" | 33.0° | 11-15/16" · 11.927" | 5-7/16" | 5-13/16" | 23.00" | ||
| 10-1/2" | 31.8° | 12-3/8"− · 12.349" | 5-1/2" | 5-3/4" | 23.50" | ||
| 11" | 30.6° | 12-3/4"+ · 12.777" | 5-5/8" | 5-5/8" | 24.00" | ||
| 10" | 35.0° | 12-3/16"+ · 12.207" | 5-3/4" | 5-1/2" | 24.00" | ||
| 10-1/2" | 33.7° | 12-5/8" · 12.619" | 5-13/16" | 5-7/16" | 24.50" | ||
| 11" | 32.5° | 13-1/16"− · 13.038" | 5-7/8" | 5-3/8" | 25.00" | ||
| 10" | 35.9° | 12-3/8"− · 12.352" | 5-7/8" | 5-3/8" | 24.50" | ||
| 10-1/2" | 34.6° | 12-3/4" · 12.760" | 5-15/16" | 5-5/16" | 25.00" | ||
| 11" | 33.4° | 13-3/16" · 13.174" | 6-1/16" | 5-3/16" | 25.50" | ||
| 10" | 36.9° | 12-1/2" · 12.500" | 6" | 5-1/4" | 25.00" | ||
| 10-1/2" | 35.5° | 12-7/8"+ · 12.903" | 6-1/8" | 5-1/8" | 25.50" | ||
| 11" | 34.3° | 13-5/16" · 13.314" | 6-3/16" | 5-1/16" | 26.00" | ||
| 10" | 37.8° | 12-5/8"+ · 12.652" | 6-1/8" | 5-1/8" | 25.50" | ||
| 10-1/2" | 36.4° | 13-1/16" · 13.050" | 6-1/4" | 5" | 26.00" | ||
| 11" | 35.2° | 13-7/16"+ · 13.456" | 6-5/16" | 4-15/16" (under 5") | 26.50" |
Clamp the stair gauges on the outside edge of the square. The throat must stay at 5" or more on cut stringers (AWC DCA 6 Fig. 28).
1:1 templates
Print, check the bar, trace.
Set your unit rise and run, then print at 100% (Actual size), landscape, on Letter or A4. Measure the 4" or 100 mm bar before cutting anything.
Stringer layout and cutting
- Total rise measured finished-to-finished at the landing spot
- Riser count = rise ÷ 7-3/4", rounded up; unit rise written on the board
- Board sighted for crown; layout on the crowned edge
- Stair gauges: rise on the tongue, run on the body
- Running marks from one hook at mark 0
- Bottom riser shortened by the tread thickness
- Saw stopped 1/4" short of every inside corner
- Throat checked: 5" or more on a 2x12
- First stringer tested on site before tracing the rest
Railing and balusters
- Clear span measured between post faces
- Gap under 4" on level guards, under 4-3/8" on stairs
- Deck-to-bottom-rail gap under 4"
- Stair bottom rail close enough for the 6" triangle
- Guard 36" above the deck, 34" above the nosings
- Posts no more than 6'-0" apart (DCA 6) or per the kit
- Marks from one hook on the post; along-rail marks for stairs
- 10% extra balusters on the order
Before the inspection
- Risers within 3/8" of each other, max 7-3/4"
- Treads at least 10" nosing to nosing
- Nosing 3/4"–1-1/4" where treads are under 11" with closed risers
- Handrail 34"–38" on stairs with four or more risers, returned at the ends
- Stringers hung on rated sloped hangers or a bolted header
- Stringers bear on posts and footings below grade or frost
- Cut-stringer span 6'-0" or less, or mid-supports added
- Stair light at the top landing switched from inside
- Width at least 36"; landing at least 36" deep
05 / Field guide
Tongue for rise,
body for run.
The framing square has laid out stairs for two centuries: set two brass stair gauges on it and it becomes a jig that draws one identical notch after another. This page shows exactly where the gauges go for your stair, the order to mark and cut, and prints a 1:1 notch template and angle protractor you can trace straight onto the board.
Setting the gauges
Screw one stair gauge to the tongue at the unit rise and the other to the body at the unit run. For a 36" deck that is 7-3/16" on the tongue and 10" on the body; the line between them is the board edge, 12-5/16" long and climbing at 35.8°.
Sight the board for crown and lay out on the crowned edge so it ends up on top.
Marking from one hook
Rather than sliding the square to the last line drawn, use the Running Tape Marks from the calculator: hook the tape at mark 0 and tick every step along the edge, then set the square to each tick. The bottom riser is then shortened by the tread thickness and squared off.
Cutting
With a circular saw, stop each cut about 1/4" before the inside corner: the blade is round, so a cut that looks finished on top has already gone past the corner underneath, and overcuts weaken the throat. Finish the corners with a handsaw or jigsaw. Cut one stringer, test it on site, then trace it for the others.
Printing at true size
Print with scaling set to 100% or "Actual size", never "Fit to page". Each template carries a 4" and 100 mm check bar: measure it before you trust the print.
Testing the first stringer
Hold the first cut stringer in place before tracing the rest. Lay a level on each tread notch: every one should read level, and each riser should measure the unit rise from the tread below with the treads in place. If the bottom step is off, the tread-thickness deduction was missed; if the top is off, the total rise was measured in the wrong place.
No stair gauges? Clamp a straight scrap of wood across the square at the two marks as a fence. It does the same job, just more slowly.
Questions
Answered plainly.
01How do you use a framing square for stairs?+−
Clamp stair gauges at the unit rise on the tongue and the unit run on the body, hold both gauges against the board edge, and trace along both legs for each step, moving the square to marks measured from one hook of the tape.
02Which side of the framing square is the tongue?+−
The shorter, narrower leg: 16" long and 1-1/2" wide. The 24" by 2" leg is the body or blade.
03Where do stair gauges go on a framing square?+−
On the outside edges: the rise mark on the tongue and the run mark on the body, so the line between them is the edge of the stringer.
04Should I cut stair stringers with a circular saw?+−
Yes for the straight runs, but stop about 1/4" short of every inside corner and finish by hand so you never cut into the throat.
05How do I print a template at actual size?+−
Choose 100% or "Actual size" in the print dialog, turn off "Fit to page", then check the printed 4" or 100 mm bar with a tape before using it.
06What angle is a 7-11 stair?+−
About 32.5°: atan(7 ÷ 11). A code-limit 7-3/4" × 10" stair is about 37.8°.