Why pitch drives material choice
Asphalt shingles need at least a 2:12 slope, and below 4:12 they require a double underlayment. Above 8:12, roofers add steep-slope labor charges because they need staging and harnesses.
- • Measure pitch safely from inside the attic against a rafter with a level.
- • Add 10–15% waste to roof area for hips, valleys, and starter courses.
- • Steeper roofs shed snow and last longer but cost more to install.
FAQ
What is a 6/12 roof pitch in degrees?
26.57 degrees. The pitch multiplier is 1.118, so the roof surface is about 11.8% larger than the building footprint.
How do I calculate rafter length?
Multiply the horizontal run (half the span plus overhang) by the pitch multiplier √(rise² + 144) ÷ 12. Add for the ridge board thickness and plumb cut.
What's the minimum pitch for shingles?
2:12 with a doubled underlayment, though 4:12 is the practical minimum most manufacturers warranty with standard installation.
How this calculator is built
Independently maintained
Written by Sam Doshi and the RevenueLab editorial team. We don't sell the data feeds this tool is built on.
Sourced from primary data
Benchmarks come from public AdSense / Stripe / IRS disclosures and reader-submitted data — never third-party "$X per view" claims. Full methodology.
Last editorial review
Reviewed on a rolling quarterly cycle. Dated reviews are published on the methodology record for each calculator.
Editorial standards
See our editorial policy and disclaimer. Results are estimates, not advice.