Stair Stringer Calculator Pro
Rise & Run, Cut List & IRC
Only for iPhone
Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.
iPhone
Lay out stair stringers in carpenter's fractions: riser count, a to-scale drawing, the cut list and an IRC and deck-stair check. Offline calculations, no subscription.
Stair Stringer Calculator lays out a straight flight of stairs from three measurements and tells you how to cut the stringers — in carpenter's fractions, not decimals.
Enter the total rise, the tallest riser you'll accept and your tread depth. You get the riser count and exact riser height, the tread count, total run, stringer length and stair angle, plus a to-scale drawing of the cut stringer.
CUT IT RIGHT
• Riser height is rounded so it never exceeds your maximum
• The first riser cut is dropped by your tread thickness, so every finished step is equal
• Framing square settings and the step-off distance along the board edge
• Notch depth and the solid wood left under the notches (throat) for a 2x10, a 2x12 or any board depth
• How many stringers to cut for your stair width, and their spacing
• Type measurements the way you read a tape: 108 1/2, 9' 0-1/2", 7 3/4
CHECK IT BEFORE YOU CUT
Every layout is checked, and the result shows what passed, not only what failed:
• IRC R311.7: maximum riser 7-3/4", minimum tread 10", maximum rise of one flight 151", minimum width 36", nosing and handrail requirements
• AWC DCA 6 deck-stair stringer limits: at least 5" of throat, a 6'-0" maximum span for cut stringers, stringers no more than 18" on center
• The stride rule 2R + T for a comfortable stair (24–25 in; 590–650 mm per DIN 18065 when you work in millimeters)
FULL CUT LIST AND PDF
• Height, run and board-edge mark for every step
• A PDF layout sheet with the drawing, cut list and code check for your crew or inspector
• Unlimited history: reopen any saved layout with its drawing and checks
INCHES OR MILLIMETERS
Switch units any time. Inch results read like a tape measure, to the nearest 1/16".
WORKS THE WAY YOU DO
• All calculations run on your device — no account or sign-in required.
• Calculations and saved history work offline on the job site
• No ads. Usage reporting can be turned off in Settings
• The app sends verified purchase records and feedback you choose to submit
• English and Spanish interface
SIMPLE PRICING
The calculation, drawing and code check are free, and the free version keeps your 10 most recent layouts. One in-app purchase unlocks the full cut list, PDF export and unlimited history. No subscription.
The formula sources are listed in the app: IRC 2021 Section R311.7, AWC DCA 6-15 Figures 28–29, and the stride rule. This app is a layout aid; always verify against the building code in force at your job site.
Ratings & Reviews
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Bug fixes and performance improvements.
The developer, 京昌 陈, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Linked to You
The following data may be collected and linked to your identity:
- Purchases
- Identifiers
- Usage Data
- Diagnostics
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- User Content
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- 京昌 陈
- Size
- 3.9 MB
- Category
- Utilities
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English and Spanish
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- Stair Stringer Pro $9.99
- Copyright
- © 2026 Jingchang Chen