8/12 Roof Pitch
Convert an 8/12 roof pitch to degrees and slope percentage, understand its steeper roof geometry, and calculate rafter length and pitch factor from rise and run.
An 8/12 roof pitch rises 8 inches for every 12 inches of horizontal run. It equals approximately 33.69°, has a 66.67% slope, and a 1.202 pitch factor.
What Does an 8/12 Roof Pitch Mean?
An 8/12 roof pitch means the roof rises 8 units vertically for every 12 units of horizontal run. Using inches, the roof gains 8 inches of height over each 12-inch horizontal section.
The same incline can be expressed as an 8/12 roof pitch angle of approximately 33.69 degrees or a 66.67% roof slope.
An 8/12 roof is noticeably steeper than common pitches such as 4/12 and 6/12. The increased incline also means the sloped roof length is greater for the same horizontal run.
Calculate an 8/12 Roof Pitch
The calculator is preloaded with an 8-inch rise and 12-inch run. Change the measurements to calculate another pitch, angle, slope or rafter length.
Enter your roof measurements and calculate instantly.
How an 8/12 Roof Pitch Is Calculated
Convert an 8-over-12 roof into angle, slope percentage and sloped length using the relationship between rise and horizontal run.
8/12 Roof Pitch Angle
Divide the rise by the run, then calculate the arctangent.
Therefore, an 8/12 roof pitch in degrees is approximately 33.69°.
8/12 Roof Slope
Slope percentage expresses the vertical rise compared with horizontal run.
An 8/12 roof therefore has a 66.67% slope.
Sloped Length
For a 12-inch horizontal run, use the right-triangle relationship.
The diagonal roof length is approximately 14.42 inches.
8/12 Rafter Length and Pitch Factor
An 8/12 roof has a longer sloped distance than lower pitches when measured across the same horizontal run.
Rafter Length per 12-Inch Run
14.42 inWith an 8-inch rise and 12-inch horizontal run, the simple diagonal distance is approximately 14.42 inches before accounting for overhang, ridge details or other framing adjustments.
8/12 Pitch Factor
1.202The 8/12 pitch factor is approximately 1.202. Multiplying a horizontal run by this factor gives the corresponding approximate sloped distance for the same pitch.
8/12 Roof Pitch Conversion Table
Quick reference values for an 8-over-12 roof incline.
| Measurement | 8/12 Value |
|---|---|
| Pitch Ratio | 8:12 |
| Angle in Degrees | 33.69° |
| Slope Percentage | 66.67% |
| Rise per 12 in Run | 8 in |
| Rafter Length per 12 in Run | 14.42 in |
| Pitch Factor | 1.202 |
How 8/12 Compares With Other Roof Pitches
Comparing roof angles makes the difference in steepness easier to see.
8/12 Pitch
33.69°66.67% slope with a pitch factor of approximately 1.202.
Rise: 8 in per 12 in run8/12 Roof Pitch FAQs
Common questions about 8/12 roof pitch, angle, slope and rafter measurements.
What is an 8/12 roof pitch in degrees?
An 8/12 roof pitch has an angle of approximately 33.69 degrees.
What percentage slope is an 8/12 roof?
An 8/12 roof has a slope of approximately 66.67%.
What does an 8/12 roof pitch mean?
It means the roof rises 8 units vertically for every 12 units of horizontal run.
What is the pitch factor for an 8/12 roof?
The 8/12 pitch factor is approximately 1.202.
What is the rafter length for an 8/12 pitch?
For exactly 12 inches of horizontal run and 8 inches of rise, the simple diagonal length is approximately 14.42 inches.
Is an 8/12 roof steeper than a 6/12 roof?
Yes. An 8/12 roof is approximately 33.69°, while a 6/12 roof is approximately 26.57°.
Can I calculate an 8/12 pitch using feet?
Yes. The pitch ratio depends on the relationship between rise and run, so both measurements can use feet or another consistent unit.
Calculate Another Roof Pitch
Use the main calculator to convert any rise and run into roof pitch, angle, slope percentage, rafter length and pitch factor.
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