StringerPro: Stair Calculator

StringerPro turns total rise + total run into a code-checked, ready-to-cut stair stringer layout.

Built for finish carpenters, framers, and deck builders who want one tool that does the stringer job exceptionally well -- not nine bundled calculators that all forget the bottom step.

KEY FEATURES

- Fraction-native input. Feet + whole inches + sixteenths picker that feels as fast as a dedicated construction calculator. Common stops (0, 1/4, 1/2, 3/4) are one tap.
- IRC R311.7 code validation. Real-time green / yellow / red badges for riser height (max 7-3/4"), tread depth (min 10"), variance (max 3/8"), 2x12 throat (min 3-1/2"), comfort (rise + tread sum), and pitch angle.
- Bottom step done right. The bottom riser is automatically shortened by the tread thickness so walking rises stay uniform once treads are installed -- a common source of uneven steps.
- Side-view diagram with all dimensions labeled. No 3D gimmicks -- just a clean 2D elevation that prints cleanly.
- Framing-square cut sheet. Step-by-step heel positions along the top edge of the 2x12, with rise leg + run leg dimensions for every notch, plus end cuts for the seat and plumb cuts.
- 1:1 print template. Tile the side view across letter or A4 pages at full scale, tape together, and trace directly onto the 2x12. Crop marks on every corner.
- Material estimator. Stringer count, stair width, and lumber prices in -- linear footage and total job cost out, including fasteners.
- Saved jobs. Job name, address, photo, and notes. One saved job on the standard tier; unlimited with premium.
- Deck stair mode. Deck-board nosing standard, concrete-pad seat cut, IRC R311.7.5 deck stair rules.
- Imperial + metric, light + dark + jobsite high-contrast themes.
- 7-day full premium trial on first install.

PREMIUM (one-time unlock, no subscription)

- Unlimited saved jobs with photos
- All three PDF exports (summary, cut sheet, 1:1 print template)
- Material estimator
- Removes ads
- Custom default thicknesses
- Jobsite high-contrast theme

DISCLAIMER

Verify all measurements before cutting. Output is for estimation only. Local building codes may vary.

Recent changes:
Fixed a crash when tapping a row on the measurement wheels.
The measurement picker now fits shorter phone screens, so Cancel and Use are always visible.
More reliable start-up when Google Play is slow to respond.