Stairs and Ramps
Stair, railing and ramp calculators checked against the residential code. Lay out stairs that pass inspection the first time, size a ramp to the 1:12 rule, and get railing heights and baluster spacing right.
Stairs
- Stair Stringer Calculator – risers, treads and stringer length
- Stair Code Requirements – riser, tread, headroom, handrail and landing rules
- Concrete Steps Calculator – concrete for solid steps
Railings and ramps
- Deck Railing Height Code – guard height and the 4 inch rule
- Ramp Slope Calculator – ramp length, landings and angle
Key numbers (IRC)
| Item | Requirement |
|---|---|
| Riser height | 7-3/4 in maximum |
| Tread depth | 10 in minimum |
| Headroom | 6 ft 8 in minimum |
| Handrail | 34 to 38 in high, required with 4 or more risers |
| Guard | 36 in minimum where the drop is more than 30 in |
| Ramp slope | 1:12 maximum (1 in of rise per 12 in of run) |
Engineer's note: inspectors fail stairs at the ends more than anywhere else: the bottom riser comes out different because the landing pad or finished floor was not counted. Measure total rise from finished surface to finished surface before cutting stringers, and keep every riser within 3/8 inch of the others.
Everything in this section
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Maintained by: Engr. Abdul Latif, civil and structural engineer. Every calculator here shows its formula and the code table it follows. For planning only; confirm with your local building department.