Layout method
How to Cut Stair Stringers With a Framing Square
Step-by-step guide to laying out and cutting stair stringers with a framing square and stair gauges, including the dropped first step and clean notch cuts.
Research Lens
What makes how to cut stair stringers with a framing square useful enough to become a repeatable app workflow?
The strongest app workflows reduce setup, keep private records local, make the next decision visible, and export or share only when the user is ready. The article focuses on the capture-review-output loop behind the app use case.
Decision Metrics
Visual model
Framing-square stringer layout
Two stair-gauge settings, rise on the tongue and run on the body, let you mark every identical step down the stringer.
The Framing Square Is Still The Core Tool
Long before calculators, carpenters laid out stairs with a framing square and a pair of stair gauges. The method still works and is worth knowing, because it lets you mark every identical step from the same two settings. The square's body and tongue become your rise and run, repeated up the board.
Set The Stair Gauges To Rise And Run
First, work out your unit rise and unit run, the height and depth of one step. Clamp one stair gauge on the square's tongue at the rise and another on the body at the run. Now every time you align both gauges to the edge of the stringer, you mark one perfect step. A calculator gives you those two numbers; the square repeats them.
Step Off The Stringer
Place the square on the 2x12 with both gauges against the board's edge and trace the rise and run. Slide the square up so the run line meets the next rise, and repeat for the full number of steps. Number each step as you go so you do not lose count. The result is a sawtooth line down the board.
Mark The Bottom And Top Cuts
The bottom of the stringer gets a level cut where it meets the floor, and the top gets a plumb cut where it meets the header. These are set by the same rise and run lines extended to the board edges. Getting these two end cuts right is what makes the stringer sit flat and plumb.
Drop The Stringer For Equal Risers
Here is the step most often missed: the bottom riser must be cut shorter by one tread thickness so that, once the treads are installed, every finished riser is equal. This dropped-stringer adjustment trips up many first-timers. Subtract the tread thickness from the bottom rise before cutting.
Cut The Notches Cleanly
Cut the notches with a circular saw up to the corner of each notch, then finish the inside corner with a handsaw or jigsaw so you do not overcut and weaken the throat. Overcutting past the corner is a common mistake that quietly reduces strength. Stop the power saw at the line and finish by hand.
Verify, Then Use It As A Template
Test-fit the first stringer in the opening before cutting the rest. Check that treads will be level and the top and bottom cuts seat properly. Once it is right, trace it to mark the others. A calculator or the Stringer app can confirm your framing-square numbers, including the dropped first step, before you commit the cuts.
Compare
Framing square vs calculator-assisted layout
| Step | Framing square alone | With a calculator | Benefit |
|---|---|---|---|
| Find rise and run | Trial and division by hand | Computed instantly | No arithmetic slips |
| Dropped first step | Remembered manually | Shown as first cut | Fewer mistakes |
| Code check | Separate lookup | Flagged automatically | Compliance confidence |
| Layout marks | Stepped off by hand | Confirmed by the app | Verify before cutting |
Field Checklist
- Set stair gauges to your unit rise and run.
- Step off and number every notch.
- Mark plumb top cut and level bottom cut.
- Drop the bottom riser by one tread thickness.
- Stop power cuts at the corner and finish by hand.
FAQ
Common questions
How do you lay out stairs with a framing square?
Set stair gauges to your unit rise on the tongue and unit run on the body, then step the square down the stringer, tracing each rise and run to mark every notch.
What are stair gauges?
Small clamps that lock onto a framing square at set positions, so you can repeat the same rise and run for every step without re-measuring.
Why drop the bottom riser?
Cutting the bottom riser short by one tread thickness makes every finished riser equal once treads are installed. Skipping it leaves an uneven first step.
How do I avoid weakening the stringer when cutting notches?
Stop the circular saw at the inside corner of each notch and finish the cut by hand. Overcutting past the corner reduces the throat and weakens the stringer.
Do I still need a calculator if I use a framing square?
No, but a calculator removes the arithmetic and confirms the dropped first step and code compliance, so your framing-square layout is right the first time.
What is the top and bottom cut on a stringer?
The top gets a plumb cut against the header and the bottom gets a level cut on the floor, both set by the same rise and run lines.
Sources