Roof Pitch Calculator
Common Roof Pitches
| Pitch | Degrees | Percent | Type |
|---|---|---|---|
| 1/12 | 4.8° | 8.3% | Flat roof |
| 2/12 | 9.5° | 16.7% | Low slope |
| 3/12 | 14.0° | 25% | Low slope |
| 4/12 | 18.4° | 33.3% | Low slope |
| 5/12 | 22.6° | 41.7% | Medium slope |
| 6/12 | 26.6° | 50% | Medium slope |
Use our Roof Pitch Calculator to determine roof pitch from rise and run measurements or convert from angle in degrees. Get accurate pitch ratios, angles, and percentages for your roofing project.
How to Measure and Calculate Roof Pitch
Method 1: Rise and Run Measurement
The most accurate way to measure roof pitch:
- Place a 2-foot level horizontally against the roof surface
- Mark exactly 12 inches along the level from one end
- Measure vertically from the 12-inch mark to the roof surface
- This vertical measurement is your rise over 12 inches of run
- Express as "X/12" where X is your rise measurement
For example, if you measure 6 inches of rise, your roof pitch is 6/12 (also called a 6:12 pitch).
Method 2: Using an Angle Finder
If you have a digital angle finder or smartphone app, you can measure the roof angle directly in degrees. Our calculator converts this to standard pitch notation.
- Place the angle finder against the roof surface
- Read the angle in degrees
- Enter this value in our calculator for automatic conversion
Understanding Pitch Classifications
- Flat/Low Slope (0/12 to 4/12): Requires special roofing materials and techniques. Water drainage is critical.
- Conventional Slope (4/12 to 9/12): Most common residential pitches. Most roofing materials work well.
- Steep Slope (9/12+): Better water runoff but more difficult and dangerous to work on. May require special installation methods.
Safety Considerations
Always prioritize safety when measuring roof pitch:
- Never work on wet or icy roofs
- Use proper safety equipment including harnesses and non-slip shoes
- For steep roofs (over 8/12), consider hiring professionals
- When possible, measure from inside the attic using rafters
- Have someone assist you and never work alone
Common Roof Pitch Applications
Different roof pitches serve different purposes and work better with certain materials. Here's what you need to know about selecting the right pitch for your project.
Material Requirements by Pitch
Low Slope (2/12 to 4/12): Requires modified bitumen, EPDM rubber, TPO, or built-up roofing. Standard asphalt shingles are not recommended due to water infiltration risk.
Standard Slope (4/12 to 9/12): Perfect for asphalt shingles, metal roofing, tile, slate, and wood shingles. This range offers the best balance of water runoff and accessibility.
Steep Slope (9/12+): All materials work well, but installation costs increase due to safety requirements and difficulty of access. May require specialized installation techniques.
Regional Considerations
- Snow Areas: Steeper pitches (6/12+) help snow slide off, reducing structural load
- High Wind Areas: Lower pitches (4/12-6/12) offer better wind resistance
- Heavy Rain Areas: Steeper pitches (5/12+) provide better water runoff
- Hot Climates: Steeper pitches improve attic ventilation and cooling
| Pitch | Degrees | Percent | Classification | Best Applications |
|---|---|---|---|---|
| 1/12 | 4.8° | 8.3% | Flat roof | Commercial buildings, modern architecture |
| 4/12 | 18.4° | 33.3% | Low slope | Ranch homes, some contemporary styles |
| 6/12 | 26.6° | 50% | Standard slope | Most residential homes, optimal balance |
| 8/12 | 33.7° | 66.7% | Medium slope | Traditional homes, good snow shedding |
| 10/12 | 39.8° | 83.3% | Steep slope | Victorian, colonial styles, snowy regions |
| 12/12 | 45.0° | 100% | Very steep | Gothic, A-frame, heavy snow areas |
Cite this page as:
Daniel, P. Roof Pitch Calculator. Available at: https://constructioncalculators.com/roof-pitch-calculator/. Accessed: October 25, 2026.