Roof Pitch Calculator

Calculate and convert roof pitch between rise/run (X-in-12), degrees, percentage, and slope ratio. Essential for roofing projects, material estimation, and building codes.

By Jordan Rivera|
Vertical rise over 12" run
Standard horizontal run is 12"
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How to Calculate Roof Pitch

Roof pitch, often expressed as "X-in-12" (like 4-in-12), is a critical measurement in construction. It determines the steepness of your roof, affecting material choices, water drainage, snow load capacity, and even attic space. Our calculator above provides instant conversions between the four common formats: Pitch, Angle in Degrees, Percentage, and Slope Ratio.

To measure pitch manually, you need two measurements: the rise (vertical height) and the run (horizontal distance). The standard convention uses a 12-inch run. So, if your roof rises 6 inches over a 12-inch horizontal distance, your pitch is 6-in-12.

Common Roof Pitch Examples

  • Low Slope (2-in-12 to 4-in-12): Common for modern homes, requires specific roofing materials.
  • Conventional Slope (4-in-12 to 9-in-12): The most common range for residential homes, suitable for asphalt shingles.
  • Steep Slope (9-in-12 and above): Found in traditional or snowy climate architecture, may require special installation.

Related Construction Calculators

Planning a full project? Use our other essential construction calculators:

  • Concrete Calculator – Figure out how much concrete you need for slabs and footings.
  • Rafter Calculator – Calculate rafter length and cuts based on roof span and pitch.
  • Roofing Calculator – Estimate shingles, underlayment, and materials for your roof.
  • Paint Calculator – Determine how much paint is needed for interior or exterior walls.

Frequently Asked Questions

What is roof pitch and how is it calculated?

Roof pitch (or slope) is the steepness of a roof, expressed as the vertical rise over a 12-inch horizontal run (e.g., 4-in-12). To calculate it, measure the vertical rise over a 12-inch horizontal distance on the roof. The formula is Pitch = Rise / Run (where Run is typically 12 inches).

What is the minimum roof pitch for shingles?

The minimum recommended roof pitch for standard asphalt shingles is 2-in-12 (about 9.5 degrees). For pitches below 4-in-12, special underlayment and installation methods are required. Always check local building codes and manufacturer specifications for your specific roofing material.

How do you convert roof pitch to degrees?

To convert pitch (X-in-12) to degrees, use the formula: Angle = arctan(Rise / Run). For example, a 6-in-12 pitch means a rise of 6 over a run of 12. arctan(6/12) = arctan(0.5) ≈ 26.57 degrees. Our calculator above performs this conversion instantly.