Quick answer: Roof pitch is written as rise-over-run — 6/12 means 6 inches of rise per 12 inches of run. Common residential pitches run 4/12 to 9/12; anything steeper than 9/12 is a steep-slope roof.
Every roof pitch from 1/12 to 12/12 explained with angles, slope percentages, and step-by-step measurement instructions.
Roof pitch is the steepness of a roof, expressed as the ratio of vertical rise to horizontal run. In the United States, pitch is almost always given as "X-in-12" — meaning the roof rises X inches for every 12 inches of horizontal distance. A "6/12 pitch" means the roof rises 6 inches for every 12 inches (1 foot) of run.
Roof pitch is different from roof slope (expressed as a percentage) and roof angle (expressed in degrees), though all three measure the same thing. Our roof pitch calculator converts between all three instantly.
| Roof Pitch | Angle (Degrees) | Slope % | Roof Type / Style | Snow Shedding |
|---|---|---|---|---|
| 1/12 | 4.8° | 8.3% | Flat / Low-slope (commercial, modern) | Poor |
| 2/12 | 9.5° | 16.7% | Minimum for asphalt shingles | Fair |
| 3/12 | 14.0° | 25.0% | Minimum for metal roofing | Moderate |
| 4/12 | 18.4° | 33.3% | Ranch, modern suburban | Good |
| 5/12 | 22.6° | 41.7% | Traditional ranch, split-level | Good |
| 6/12 | 26.6° | 50.0% | Most common US residential pitch | Very Good |
| 7/12 | 30.3° | 58.3% | Craftsman, Cape Cod | Very Good |
| 8/12 | 33.7° | 66.7% | Colonial, traditional two-story | Excellent |
| 9/12 | 36.9° | 75.0% | Victorian, steep traditional | Excellent |
| 10/12 | 39.8° | 83.3% | A-frame, Gothic revival | Excellent |
| 11/12 | 42.5° | 91.7% | Swiss chalet, steep A-frame | Outstanding |
| 12/12 | 45.0° | 100.0% | A-frame, Gothic, church steeple | Outstanding |
The safest method — no ladder required. Go into your attic with a level and tape measure. Find a rafter. Place your level against the bottom edge of the rafter, holding it perfectly horizontal. Measure 12 inches out from one end along the level. Then measure straight down (or up) from the level to the rafter at the 12-inch mark. That measurement is your rise. Example: if it's 6 inches, you have a 6/12 pitch.
Stand far enough from the house to see the full gable end. Use a level app on your phone (or a physical level) held horizontally. Align the edge of your phone with the roof line and the app will show the angle in degrees. Convert using our roof pitch calculator or use this formula: tan(angle) × 12 = rise. So a 26.6° roof = tan(26.6) × 12 = 0.5 × 12 = 6/12 pitch.
On the roof, hold a 12-inch level horizontally against the roof surface. Measure the vertical distance from the end of the level down to the roof. That's your rise. This is the most accurate method but requires working on the roof — use proper fall protection.
We keep four separate roof-pitch pages because people arrive with four different questions. If this is not the one you wanted:
6/12 (26.6°) is the single most common residential roof pitch in the United States, followed by 4/12 and 8/12. 6/12 offers a good balance of aesthetics, attic space, water/snow shedding, and construction cost.
In areas with heavy snowfall, a minimum of 6/12 is recommended. Pitches of 8/12, 10/12, and 12/12 are common in mountain regions. Steeper roofs allow snow to slide off rather than accumulate and cause ice dams or structural stress.
Generally safe to walk on pitches up to 6/12 without special equipment. 7/12 to 9/12 requires roofing jacks or toe boards. 10/12 and above requires full safety harnesses and should be left to professionals.
Roof pitch is expressed as a ratio of rise over 12 inches of run (e.g., 6/12). Roof slope is the same thing expressed as a percentage (6/12 = 50% slope). Roof angle is expressed in degrees (6/12 = 26.6°). They're three ways of describing the same measurement.
Measure the building footprint and multiply by the pitch factor: 4/12 = 1.054, 6/12 = 1.118, 8/12 = 1.202, 10/12 = 1.302, 12/12 = 1.414. So a 2,000 sq ft footprint with a 6/12 pitch = 2,236 sq ft of roof area. Use our roof shingle calculator for exact numbers.
Every constant this calculator uses and where it comes from, so you can check it rather than take our word for it.
Local codes amend the model IRC and adopt different cycles — your building department governs. Manufacturers revise yields; where your product's data sheet disagrees with a default here, use the product's number. See our full methodology.