Stair Calculator
IRC-compliant layouts: 2R+T comfort rule included.
15 risers (7.2" each)
14 treads · stringer 182.4"
- Stair angle
- 34.4°
- Comfort rule 2R+T
- 24.9" (ideal 24–25")
- IRC check
- Rise OK · Run OK
How the Stair Calculator works
The calculation follows the standard method used across the US — no shortcuts, no hidden assumptions. Here is exactly what happens behind the scenes:
Frequently Asked Questions
How does the Stair Calculator work?
Enter your numbers above and results update instantly using standard formulas, computed entirely on your device.
Is the Stair Calculator free to use?
Yes — completely free with no signup required, and it works on phones, tablets, and desktops.
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