Roof Pitch Calculator
Calculate your roof pitch using rise/run, angle, or visual selection. Get material recommendations, labor difficulty ratings, and safety requirements.
Calculate Your Roof Pitch
Vertical height over the run distance
Standard is 12 inches (1 foot)
How to Measure Rise & Run
Place a level horizontally at 12 inches, then measure the vertical distance from the level to the roof surface. That vertical measurement is your rise.
Enter the "flat" footprint area to calculate actual roof surface area
Common Roof Pitch Reference
| Pitch | Degrees | Category | Labor Factor | Common Uses |
|---|---|---|---|---|
| 1/12 - 2/12 | 4.8° - 9.5° | Flat/Low | 1.0x | Commercial buildings, additions, porches |
| 3/12 - 4/12 | 14° - 18.4° | Low Slope | 1.05x | Ranch homes, contemporary designs |
| 5/12 - 7/12 | 22.6° - 30.3° | Conventional | 1.10x | Most common residential, works with all materials |
| 8/12 - 9/12 | 33.7° - 36.9° | Steep | 1.20x | Cape Cod, Colonial, high rain/snow areas |
| 10/12 - 12/12 | 39.8° - 45° | Very Steep | 1.30x | Victorian, Gothic, heavy snow regions |
| 14/12+ | 49.4°+ | Extreme | 1.50x+ | A-frames, church steeples, specialty designs |
Understanding Roof Pitch
What is Roof Pitch?
Roof pitch is the measurement of a roof's slope, expressed as a ratio of vertical rise to horizontal run. A "6/12 pitch" means the roof rises 6 inches for every 12 inches of horizontal distance. Understanding your roof's pitch is essential for material selection, cost estimation, and safety planning.
Why Roof Pitch Matters
Material Selection
Different materials have minimum pitch requirements. Asphalt shingles typically need 4/12 minimum, while metal roofing can work with 3/12. Flat roofs require membrane systems.
Cost Impact
Steeper pitches increase both material needs (larger surface area) and labor costs (safety equipment, slower work pace). A 12/12 pitch can cost 30-40% more than 4/12.
Weather Performance
Higher pitches shed water and snow more effectively but may be more susceptible to wind uplift. Lower pitches need better waterproofing but are more wind-resistant.
Attic Space
Steeper pitches create more usable attic space, better natural ventilation, and potential for living space or storage. Low pitches limit attic functionality.
Minimum Pitch Requirements by Material
- Flat Roofing:1/4"/12 to 2/12 (TPO, EPDM, built-up)
- Metal:3/12 minimum (standing seam), 4/12 (exposed fastener)
- Shingles:4/12 standard, 2/12-4/12 with special underlayment
- Tile/Slate:4/12 minimum, 5/12+ recommended
- Wood Shakes:4/12 minimum for proper drainage
Frequently Asked Questions
What is the most common roof pitch?
The most common roof pitch in the United States is 4/12 to 6/12. This range offers a good balance of aesthetics, drainage, cost, and compatibility with most roofing materials. In areas with heavy rain or snow, 6/12 to 8/12 is more common for better water shedding.
How do I measure my roof pitch without going on the roof?
You can measure roof pitch from inside your attic. Place a level horizontally against a rafter, mark 12 inches from where the level touches the rafter, then measure straight up from that mark to the bottom of the rafter. That vertical measurement is your rise. Alternatively, use a smartphone app with an inclinometer against the ceiling in the attic.
What roof pitch is considered walkable?
Generally, roofs with a pitch of 6/12 or less are considered walkable for most people, though 4/12 or less is comfortable for extended work. Pitches from 7/12 to 9/12 require caution and possibly toe boards. Anything 10/12 and above typically requires safety equipment like harnesses and roof jacks.
Does roof pitch affect home insurance?
Yes, roof pitch can affect insurance rates. Steeper roofs (8/12+) may get slightly better rates in areas prone to heavy rain or snow due to better drainage. However, very steep roofs can be penalized in high-wind areas. The bigger factor is usually roofing material and age.
Can I change my roof pitch?
Changing roof pitch is possible but expensive as it requires major structural modifications. Common reasons include adding living space in the attic or improving drainage. The cost typically ranges from $15,000 to $50,000+ depending on roof size and the extent of changes needed.
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Get a Professional Roof Assessment
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