Enter your rise and run to get roof pitch, angle, and slope factor.
Roof pitch is how steep your roof is — measured as the vertical rise for every 12 inches of horizontal run. Enter your measurements below to get the pitch (X-in-12), the angle in degrees, and the slope factor used to estimate roof area. Once you know your pitch, use our roofing squares calculator to estimate materials.
Tip: to measure, hold a level flat against the roofline, mark 12 inches, and measure straight down to the roof at that mark — that drop is your rise over a 12-inch run.
Roof pitch is the steepness of your roof, written as the vertical rise per 12 inches of horizontal run — so a "6:12" roof rises 6 inches for every foot it travels across. It's the single number that determines which roofing materials you can use, how much material a roof needs, and how much a job costs to install safely.
You don't need to get on the roof. Grab a 12-inch level and a tape measure and use the "12-inch level method":
| Pitch | Category | Best materials |
|---|---|---|
| Below 3:12 | Low-slope / flat | TPO, PVC, modified bitumen, coatings |
| 4:12 – 9:12 | Conventional | Asphalt shingles, metal, tile — most Houston homes |
| 10:12 and up | Steep | Shingles, metal, slate — higher install cost |
Houston gets 50+ inches of rain a year, so drainage is everything — a steeper pitch sheds water and debris faster. Pitch also drives cost two ways: a steeper roof has more surface area than its footprint (that's the slope factor), and steep roofs are slower and safer-equipment-intensive to walk, so labor runs higher. Low-slope sections below 3:12 can't use standard shingles at all — they need a flat-roof membrane. If you're pricing a project, plug your pitch into the roofing squares calculator, then see real numbers on our roof replacement cost and roof cost calculator pages. Want to know what every part of that roof is called? See our parts of a roof guide.
Not sure of your pitch or which material fits it? Call RISE Roofing at (832) 224-3435 for a free roof measurement and estimate.
Roof pitch is the steepness of a roof, expressed as the number of inches it rises vertically for every 12 inches of horizontal run — written as X-in-12 (for example 6:12). A 6:12 roof rises 6 inches for every 12 inches across.
Place a level horizontally against the roof, mark 12 inches along it, then measure straight down from the 12-inch mark to the roof surface. That vertical measurement is your rise over a 12-inch run — the X in X-in-12. You can measure on the roof, in the attic against a rafter, or from a gable end.
The slope factor is a multiplier that converts your flat footprint area into actual roof surface area. A steeper roof has more surface than its footprint. For example, a 6:12 roof has a slope factor of about 1.118, so a 2,000 sq ft footprint is about 2,236 sq ft of roof — which is what you actually pay to shingle.
Most Houston homes use a conventional pitch between 4:12 and 9:12, which sheds our heavy rain well and works with asphalt shingles and metal. Pitches below 3:12 are low-slope and usually need a membrane system; pitches above 9:12 are steep and cost more to install safely.
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