96" rise, 120" run
- Steps = 14
- Risers ≈ 6.86"
- Treads ≈ 8.57"
construction calculator
Stair Stringer Calculator
Determine risers, tread depth, and stringer length from total rise and run.
Results
- Number of steps
- 14.00
- Actual riser height (in)
- 6.86
- Tread depth (in)
- 8.57
- Stringer length (in)
- 153.67
How to use this calculator
- Enter total rise and run plus your preferred riser height.
- We determine the number of steps, adjust actual riser height and tread depth, and compute stringer length.
- Use the results to mark and cut stringers before adding treads and nosing.
Inputs explained
- Total rise
- Vertical height from lower floor/landing to upper floor/landing.
- Total run
- Horizontal distance available for the stair run.
- Preferred riser height
- Target riser height in inches; we adjust to an even value across all steps.
How it works
We divide total rise by preferred riser height to determine step count, then recompute actual rise/run per step.
Stringer length comes from the Pythagorean theorem using total rise and run.
Formula
Steps = ceil(total rise / preferred rise)\nTread depth = total run / steps
When to use it
- Laying out deck stairs that meet common code ranges.
- Checking if a staircase fits in the available run before framing walls.
- Comparing different riser heights for comfort versus available space.
Tips & cautions
- Check local code for maximum riser and minimum tread depth; adjust inputs accordingly.
- Add nosing after cutting—the tread depth output is between risers, not including nosing overhang.
- Round step count to a whole number that keeps risers within code and comfortable to climb.
- Does not include landings, winders, or split runs—use straight-run stairs only.
- Assumes uniform risers and treads; irregular steps need custom layout.
- Stringer material and notch depth requirements are not validated—verify lumber sizing separately.
Worked examples
108" rise, 144" run
- Steps = 16
- Risers ≈ 6.75"
- Treads = 9"
Deep dive
Design stair stringers by entering total rise, run, and target riser height to get step count, tread depth, and stringer length.
Use it to sanity-check deck or interior stair layouts against comfort and code before you cut lumber.
FAQs
- Does this include nosing?
- Add nosing after cutting. The tread depth output is the run between risers.
- Are there code limits?
- Most codes require risers between 4"–7.75" and treads ≥ 10". Always verify local requirements.
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Use this as a planning guide. Confirm final layout against building codes before cutting lumber.