Stair Angle Calculator
Calculate the stair angle (inclination) from rise and run dimensions. Check if your stairs meet building code.
Enter rise and run.
Stair Angle Formula
Angle = arctan(Rise / Run)
Safe Stair Angles
- Comfortable: 30°–35°
- Acceptable: 20°–45°
- Steep/ladder: 45°–75°
Building codes typically require risers ≤ 7.75″ and treads ≥ 10″.
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Last updated: 2026-08-08