Roof Pitch Calculator
Calculate roof pitch, angle, and area multiplier from rise/run measurements. Convert between pitch ratio, degrees, and grade percentage.
How to Use This Calculator
Knowing your roof pitch is essential for ordering materials and planning roofing projects. Here's how to calculate it:
- Choose your input method: rise and run measurements, angle in degrees, or pitch ratio (X/12).
- Enter your measurements. For rise/run, measure the vertical rise over a known horizontal distance (typically 12 inches).
- Optionally enter your roof footprint area to calculate actual roof surface area.
- Click 'Calculate' to see pitch ratio, angle, and area multiplier.
- Use the reference table to compare with common roof pitches.
Why This Matters
Roof pitch affects everything from material choices to worker safety. Low-slope roofs (under 2/12) can't use standard shingles. Steep roofs (over 7/12) require safety equipment. The pitch also determines how much roofing material you need - steeper roofs have significantly more surface area than their footprint suggests.
- Convert between pitch ratio, angle, and grade percentage
- Calculate the pitch multiplier for accurate material ordering
- Determine if standard shingles are appropriate for your roof
- Know when safety equipment is required for roof work
- Calculate actual roof area from footprint measurements
Worked Examples
Measuring from the Attic
You measure 8 inches of rise over 12 inches of run from inside the attic.
Converting Angle to Pitch
A roofing contractor quotes work for a 30-degree roof.
Low-Slope Verification
Checking if a porch roof can use standard shingles.
Common Mistakes to Avoid
- Confusing pitch with angle - a 6/12 pitch is NOT 6 degrees; it's 26.6 degrees.
- Measuring run on the slope instead of horizontally - run must be horizontal distance.
- Using footprint area for material ordering - apply the pitch multiplier for actual roof area.
- Assuming low-slope roofs can use standard shingles - below 2/12 requires special materials.
- Not accounting for both sides of a gable roof - measure one side and double if symmetrical.