Roof Pitch to Degrees Conversion Chart
A complete reference table for converting roof pitch (x:12 ratio) to degrees, percentage slope, and pitch factor — plus the formula to convert any pitch you encounter.
The conversion formula
Roof pitch in the US is expressed as x:12 — the number of inches of rise per 12 inches of run. To convert to degrees:
To convert degrees back to x:12 pitch:
To convert x:12 to percentage slope:
Complete conversion table
| Pitch (x:12) | Degrees | % slope | Pitch factor | OSHA category |
|---|---|---|---|---|
| 1:12 | 4.76° | 8.3% | 1.003 | Low slope |
| 2:12 | 9.46° | 16.7% | 1.014 | Low slope |
| 3:12 | 14.04° | 25.0% | 1.031 | Low slope |
| 4:12 | 18.43° | 33.3% | 1.054 | Low slope |
| 5:12 | 22.62° | 41.7% | 1.083 | Steep |
| 6:12 | 26.57° | 50.0% | 1.118 | Steep |
| 7:12 | 30.26° | 58.3% | 1.158 | Steep |
| 8:12 | 33.69° | 66.7% | 1.202 | Steep |
| 9:12 | 36.87° | 75.0% | 1.250 | Steep |
| 10:12 | 39.81° | 83.3% | 1.302 | Steep |
| 11:12 | 42.51° | 91.7% | 1.357 | Steep |
| 12:12 | 45.00° | 100.0% | 1.414 | Steep |
| 14:12 | 49.40° | 116.7% | 1.537 | Steep |
| 16:12 | 53.13° | 133.3% | 1.667 | Steep |
Worked examples
Example 1 — x:12 to degrees
Example 2 — degrees to x:12
Example 3 — pitch factor for material ordering
Minimum pitch by roofing material
The 2024 International Residential Code (IRC) sets a minimum slope for each roof covering in Section R905:
| Roof covering | Minimum pitch | 2024 IRC |
|---|---|---|
| Built-up roofing (coal-tar) | ¼:12 (⅛:12) | R905.9.1 |
| Standing-seam metal panels | ¼:12 | R905.10.2 |
| Modified bitumen | ¼:12 | R905.11.1 |
| Single-ply membrane (EPDM, TPO, PVC) | ¼:12 | R905.12.1 |
| Sprayed polyurethane foam | ¼:12 | R905.13.1 |
| Liquid-applied roofing | ¼:12 | R905.14.1 |
| Lapped metal panels with lap sealant | ½:12 | R905.10.2 |
| Mineral-surfaced roll roofing | 1:12 | R905.5.2 |
| Asphalt shingles | 2:12 (double underlayment below 4:12) | R905.2.2 |
| Clay and concrete tile | 2½:12 (double underlayment below 4:12) | R905.3.2 |
| Metal roof shingles | 3:12 | R905.4.2 |
| Wood shingles / wood shakes | 3:12 | R905.7.2 / R905.8.2 |
| Lapped metal panels without lap sealant | 3:12 | R905.10.2 |
| Slate shingles | 4:12 | R905.6.2 |
Convert any pitch instantly
Enter rise and run, degrees, or x:12 ratio — get all conversions, rafter length, and true roof area in one step.
Use the Roof Pitch Calculator →FAQ
How do I convert roof pitch to degrees?
Use arctan(rise ÷ 12) × (180 ÷ π). For a 6:12 pitch: arctan(6 ÷ 12) = arctan(0.5) = 26.57°. Most scientific calculators have an arctan (tan⁻¹) button. The roof pitch calculator on this site handles the conversion instantly.
What is a 4:12 pitch in degrees?
A 4:12 pitch equals 18.43°. Use arctan(4 ÷ 12) = arctan(0.333) = 18.43°. It is the upper limit of a low-slope roof under OSHA 29 CFR 1926.500 (anything steeper is a steep roof). In the 2024 IRC it is the minimum slope for slate and the point at which asphalt shingles and tile no longer need double underlayment.
What is a 6:12 pitch in degrees?
A 6:12 pitch equals 26.57° (50% slope, pitch factor 1.118). Because it is over 4:12, OSHA classifies it as a steep roof: for construction work 6 ft or more above a lower level, guardrails with toeboards, safety nets or personal fall arrest are required.
How do I convert degrees back to x:12 pitch?
Use tan(degrees) × 12. For 30°: tan(30°) = 0.577 × 12 = 6.93, so a 30° roof is a 6.93:12 pitch — about 7:12 when rounded to a whole number.
What angle is a 12:12 pitch?
A 12:12 pitch is exactly 45° — the roof rises as much as it runs horizontally (100% slope, pitch factor 1.414). Pitches above 12:12 give angles greater than 45°.