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Material Suitability at This Pitch
| Material | Typical minimum | At your pitch |
|---|---|---|
| Asphalt shingles | 2:12 (4:12 ideal) | — |
| Standing-seam metal | 1:12 | — |
| Clay / concrete tile | 2.5:12 (4:12 ideal) | — |
| Low-slope membrane | up to ~3:12 | — |
Pitch Visual Comparison
Pitch to Angle Chart
| Pitch | Angle | Slope | Category |
|---|---|---|---|
| 2:12 | 9.5 deg | 17% | Low slope |
| 4:12 | 18.4 deg | 33% | Standard |
| 6:12 | 26.6 deg | 50% | Standard |
| 8:12 | 33.7 deg | 67% | Standard / steep |
| 10:12 | 39.8 deg | 83% | Steep |
| 12:12 | 45 deg | 100% | Steep |
Minimum Pitch by Roofing Material
| Material | Minimum pitch |
|---|---|
| Built-up / single-ply membrane | 1/4:12 (flat to low) |
| Standing-seam metal | 1:12 |
| Asphalt shingles | 2:12 (special underlayment 2-4:12) |
| Clay / concrete tile | 2.5:12 to 4:12 |
| Wood shake | 4:12 |
What Is Roof Pitch?
Roof pitch is how steep a roof is, expressed as the rise in inches for every 12 inches of horizontal run. A 6:12 pitch rises 6 inches over a foot of run. The same steepness can be written several ways, which is why this tool converts between them: the X:12 pitch, the angle in degrees, the slope as a percentage, and the rise-to-run ratio. Enter any one of those and it returns the rest, then tells you what category the roof falls into and which roofing materials suit it.
Pitch, Angle, and Slope Percent
These three describe the same thing differently. The pitch X:12 is the builder shorthand. The angle in degrees is the actual incline, found with the arctangent of rise over run, so 6:12 is 26.6 degrees. The slope percentage is rise divided by run times 100, so 6:12 is 50 percent and a 12:12 roof is 100 percent, which is 45 degrees, not 100 degrees. Mixing up percent and degrees is the most common pitch mistake, and seeing all three together makes the relationship clear.
Minimum Pitch by Material
Every roofing material has a minimum pitch below which water sits too long and leaks. Membrane systems handle nearly flat roofs down to a quarter inch per foot. Standing-seam metal works from about 1:12. Asphalt shingles need at least 2:12, and ideally 4:12 or more, with special underlayment required on the low end. Tile generally wants 2.5:12 to 4:12, and wood shakes 4:12. This calculator flags whether your pitch is suitable, marginal, or too low for each common material.
Roof Safety and Steep Pitches
Pitch is also a safety question. Roofs up to about 6:12 are generally walkable with care. From 7:12 the surface gets slick and a slip becomes a fall, and from around 8:12 up, working safely needs roof jacks, toe boards, a harness with proper anchorage, or scaffolding. Steep and very steep roofs are best left to professionals with fall protection. Knowing the angle before you climb up tells you what you are dealing with.
Frequently Asked Questions
What is a normal roof pitch? Most homes fall between 4:12 and 8:12, the conventional or standard range.
What pitch is too low for shingles? Below 2:12 shingles should not be used; use a membrane or metal instead.
How do I convert pitch to degrees? Take the arctangent of the rise divided by the run; 6:12 gives 26.6 degrees.
Is 12:12 a 100 percent slope? Yes, a 12:12 roof rises as much as it runs, which is 100 percent slope and 45 degrees.