Stair Stringer Calculator
Stair Stringer Calculator
Calculate precise stair stringer dimensions and layout for building safe, code-compliant stairs. This professional stringer calculator provides cutting measurements, angles, and material requirements.
Stair Stringer Basics:
- Stringers: structural supports that carry stair loads
- Typical spacing: 16" on center, maximum 24"
- Material: 2×12 lumber for spans up to 14 feet
- Number needed: 3 stringers for stairs up to 36" wide
Building Code Requirements:
- Riser height: 4" minimum, 7.75" maximum
- Tread depth: 10" minimum (residential)
- Variation: ±3/8" between risers and treads
- Headroom: 6'8" minimum clear height
Stringer Layout Process:
- Calculate: total rise and run
- Determine: number of risers and treads
- Mark: stringer board with square
- Cut: with circular saw and jigsaw
Common Stringer Lumber:
- 2×10: spans up to 12 feet
- 2×12: spans up to 14 feet (most common)
- 2×14: spans over 14 feet (special order)
- LVL/Engineered: longer spans, higher loads
Tools Required:
- Framing square: for layout marking
- Circular saw: main cuts
- Jigsaw: plunge cuts and curves
- Level: checking alignment
Frequently Asked Questions
How many stringers do I need for 36-inch stairs?
3 stringers for stairs up to 36" wide. Add one stringer for every additional 16" of width. Use 16" spacing for maximum support.
What size lumber for stair stringers?
2×12 lumber is standard for most residential applications up to 14 feet. Use 2×10 for shorter spans or 2×14 for longer spans.
How do I cut stair stringers?
Mark with framing square, cut with circular saw for straight cuts, finish inside corners with jigsaw. Use first stringer as template for others.
What's the maximum stringer span?
2×12 stringers can span up to 14 feet. For longer spans, use engineered lumber or add a beam support underneath.
How do I attach stringers to deck or floor?
Use joist hangers at the top, concrete anchors or bolts at the bottom. Follow local building codes for connection requirements.
Can I notch stringers for treads?
Yes, but maintain minimum 5" of material below the tread cut. Deeper cuts weaken the stringer and may violate building codes.