Roof Pitch Calculator
Calculate roof pitch ratio, slope percentage, angle and rafter length from rise, run and horizontal span. Enter current dimensions and local assumptions to produce a transparent planning estimate.
Fill in the required fields to see your result.
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The primary output summarizes the main quantity or estimated cost. Supporting outputs expose intermediate area, volume, weight and cost calculations.
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How to Use This Calculator
Enter field measurements using the units shown. Replace example densities, prices and allowances with current supplier or project values.
Formula & Methodology
The calculator applies visible geometry, quantity and cost formulas to the entered values. It does not add hidden labor, permit, engineering, delivery or tax assumptions.
Worked example
A rise of 6 inches over a 12-inch run is a 6-in-12 pitch, equal to a 50% slope.
Preliminary planning estimate only. Final quantities and costs may differ because of site conditions, cuts, waste, compaction, moisture, product dimensions, installation methods and local requirements.
Verify field measurements, product specifications, supplier conversion factors, structural requirements and local code before ordering materials or beginning construction.
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Related Guides
- Roof Pitch Calculator: How to Measure, Calculate & Use Roof PitchCalculate roof pitch from rise and run. Understand pitch notation, how pitch affects material needs, which pitches work for different materials, and how to convert pitch to degrees.
- How to Calculate Roof Rafters: Span, Rise, Pitch, and Rafter LengthCalculate common rafter length from roof pitch, span, and ridge board size. Covers the Pythagorean theorem approach, roof pitch rise-per-foot, and how to account for overhang and ridge reduction.
Frequently Asked Questions
- What does the Roof Pitch Calculator calculate?
- Calculate roof pitch ratio, slope percentage, angle and rafter length from rise, run and horizontal span.
- Is the estimate exact?
- No. It is a planning estimate based on the dimensions, prices, densities, waste factors and other assumptions entered.
- Can I use local prices and supplier data?
- Yes. Replace every example value with current local quotes, product dimensions, densities and installation requirements.
- Should I verify the quantities before ordering?
- Yes. Confirm field measurements, product coverage, compaction, waste, structural requirements and supplier conversion factors before ordering materials.
Last updated 7/21/2026