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Roof pitch to degrees (and degrees to pitch)

Roof pitch is often written as a ratio (like 6/12), while protractors read degrees. This guide shows how to convert both ways and sanity-check your result on an image.

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Pitch vs degrees (quick definitions)

Roof pitch ratio describes rise over run. In the US it’s commonly written as x/12 (rise per 12 inches of horizontal run).

Roof pitch angle (degrees) is the angle between the roof slope line and a true horizontal baseline.

If you can measure the slope angle on a photo/plan, you can convert it to a pitch ratio. If you only have a pitch ratio, you can convert it to degrees to compare with drawings and specs.

Step-by-step

  1. 1
    Choose what you’re converting
    Decide whether you’re going from pitch ratio → degrees, or degrees → pitch ratio. If your input is x/12, treat it as rise/run with run = 12.
  2. 2
    Get a clean image (optional but recommended)
    If you have a roof photo or plan, upload it so you can verify the angle visually. For photos, try a clear side profile to reduce perspective distortion.
  3. 3
    Align a true horizontal baseline
    Rotate/flip and use the grid so a known horizontal edge becomes perfectly level. This baseline is what the degree angle references.
  4. 4
    Measure the slope angle in degrees
    Place the center at the slope start point and align one side to the baseline. Rotate the other side to match the roof slope edge and read the angle.
  5. 5
    Convert and export your result
    Use the measured degrees to compute/compare the pitch ratio (or convert your pitch ratio into degrees). Export PNG/PDF to document the angle and your source image.

Tips

  • Don’t trust a skewed photo. If the camera isn’t perpendicular to the roof face, the measured degrees can be biased.
  • Alignment is the fastest accuracy win. A slightly tilted baseline can change the pitch degrees noticeably.
  • If the pitch is near a common value (like 4/12, 6/12, 8/12), try Snap modes to quickly check if the image matches a clean angle.
Alignment checklistMeasure roof pitch (slope) angleDegrees vs radians (basics)

Related

Measure roof pitch (slope) angle
Measure the slope angle in degrees from a roof photo or plan, then export a shareable result.
Measure an angle on a blueprint
If you have plans, the blueprint workflow is usually more stable than a camera photo.
Measure an angle from a camera photo
When you only have an on-site photo, follow the camera workflow and prioritize alignment.
PNG and PDF exports
Save a shareable image or a report once your conversion is verified.
Roof Pitch to Degrees (and Degrees to Pitch) | Smart Protractor