Roof Pitch Calculator
Find roof pitch, angle, slope and surface-area multiplier.
Enter your project details
Each dimension can use its own unit—for example feet for length and inches for thickness. Package counts are rounded up.
Formula and calculation steps
Multiplier = √(run² + rise²) ÷ run- Measure 4 rise over 12 horizontal run.
- Calculate angle and slope.
- Use 1.054× in the roofing calculator.
Worked example
Measure vertical rise over a 12-inch horizontal run; use the multiplier in the roofing calculator.
How to use this calculator
- Measure vertical rise over a known horizontal run.
- Enter rise and run.
- Use pitch, angle and multiplier with area or shingle calculators.
Example: Measure vertical rise over a 12-inch horizontal run; use the multiplier in the roofing calculator.
Questions about this calculator
What does the pitch multiplier do?
It converts horizontal plan area into actual roof surface area for material estimates.
Is 6/12 the same as 26.57°?
Approximately yes—6/12 pitch is about 26.57 degrees; the calculator shows both.
Can I use mixed units?
Yes. Choose feet, inches, metres or centimetres and the calculator converts each input before calculating.
Is this a final material order?
No. Confirm drawings, product coverage, local code and site conditions before buying or building.
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<iframe src="https://www.buildcalclab.com/embed/roof-pitch-calculator/?theme=light" width="100%" height="640" title="BuildWise calculator" style="border:0;max-width:720px"></iframe>Assumptions and references
Results are estimates based on the dimensions and values you enter. Verify final quantities, manufacturer coverage and site-specific requirements before ordering.
Last reviewed: July 2026 · Read our calculation methodology