Roof Pitch Calculator
Pitch ↔ angle ↔ rafter length from span and rise.
4/12–6/12 suits most asphalt shingles; under 2/12 demands membrane roofing; metal sheets live happily at 3/12+. Snow country goes steep for shedding.
Formula
Disclaimer: This tool is for general informational and estimation purposes only and is not professional financial, tax, accounting or legal advice. All figures are estimates — verify with a qualified professional before making decisions. Read the full disclaimer.
Roof Pitch Calculator is a free roof pitch for surveyors, civil engineers and property buyers — instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Roof Pitch Calculator
Pitch ↔ angle ↔ rafter length from span and rise. The calculation implements pitch = rise/half-span × 12; rafter = √(rise² + run²) + overhang (Carpentry framing practice; roofing minimum slopes). 4/12–6/12 suits most asphalt shingles; under 2/12 demands membrane roofing; metal sheets live happily at 3/12+. Snow country goes steep for shedding.
How to use Roof Pitch Calculator
- 1Enter Building span (wall to wall) in m.
- 2Enter Ridge rise above walls in m.
- 3Enter Eave overhang (each side) in m.
- 4Read Pitch (x in 12), Angle, Rafter length (incl. overhang) instantly — no submit button needed.
- 5Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Roof Pitch Calculator?
- ✓Implements the standard formula — pitch = rise/half-span × 12; rafter = √(rise² + run²) + overhang
- ✓Reference cited on-page: Carpentry framing practice; roofing minimum slopes
- ✓One-click SI ⇄ Imperial toggle — values convert in place, physics stays in SI
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Roof Pitch Calculator use?+
It computes pitch = rise/half-span × 12; rafter = √(rise² + run²) + overhang, per Carpentry framing practice; roofing minimum slopes. The formula is displayed under the result.
What should I keep in mind when using this calculator?+
4/12–6/12 suits most asphalt shingles; under 2/12 demands membrane roofing; metal sheets live happily at 3/12+. Snow country goes steep for shedding.
Are regional land units exact?+
Conversion factors follow state revenue-department values noted on the tool. Units like bigha and katha vary by region, so always confirm the local factor named in your land records.
Is the Roof Pitch Calculator free to use?+
Yes — completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
Related Engineering tools
Reynolds Number Calculator
Compute Re from density, velocity, pipe diameter and viscosity — with instant laminar/turbulent classification.
● LiveLaminar vs Turbulent Flow Classifier
Classify hydraulic-oil or process-fluid flow regime from kinematic viscosity, line velocity and tube bore.
● LiveBernoulli Equation Solver
Solve downstream pressure between two points from velocities, elevations and fluid density (ideal, lossless).
● Live