Roof Pitch Calculator
Calculate roof pitch, slope, angle, and rise/run measurements instantly
Enter measurements to calculate roof pitch
Quick Examples
What is Roof Pitch?
Roof pitch, also known as roof slope, refers to the amount of vertical rise of a roof over a corresponding horizontal distance (run). It's typically expressed as a ratio, such as 6:12, which means the roof rises 6 inches for every 12 inches of horizontal run.
Understanding roof pitch is crucial for construction, roofing material selection, and calculating the amount of materials needed for a project. The pitch affects water drainage, snow load capacity, and the overall aesthetic of the building.
How to Use This Calculator
Choose Calculation Method
Select whether you want to calculate from rise/run measurements, angle, or pitch ratio
Enter Your Measurements
Input your known values (rise and run, angle, or pitch ratio)
Get Instant Results
View comprehensive results including pitch ratio, angle, percentage, and rafter multiplier
Common Roof Pitch Types
Low Slope (2:12 to 4:12)
Low slope roofs are nearly flat and require special waterproofing materials. They're common in commercial buildings and modern residential designs. Limited roofing material options available.
Conventional Slope (4:12 to 9:12)
This is the most common pitch range for residential roofs. It provides good water drainage, works with most roofing materials, and is suitable for most climates. The 6:12 pitch is especially popular.
Steep Slope (9:12 and above)
Steep roofs are excellent for areas with heavy snow or rainfall. They provide maximum drainage and create dramatic architectural statements. May require special installation techniques and safety equipment.
Understanding Roof Pitch Terms
Pitch Ratio (X:12)
The number of inches the roof rises vertically for every 12 inches of horizontal run. For example, a 6:12 pitch rises 6 inches per foot.
Roof Angle
The angle in degrees between the roof surface and a horizontal plane. This is useful for trigonometric calculations and building code compliance.
Rafter Multiplier
The factor used to calculate the length of rafters. Multiply the horizontal run by this number to get the actual rafter length needed.
Slope Percentage
The pitch expressed as a percentage. This is the rise divided by the run, multiplied by 100. Often used in construction drawings and specifications.
Frequently Asked Questions
What is the most common roof pitch?
The most common roof pitch for residential homes is 6:12 (6 inches of rise for every 12 inches of run), which equals approximately 26.57 degrees. This pitch provides good water drainage and works well with most roofing materials.
How do I measure roof pitch on an existing roof?
You can measure roof pitch using a level and measuring tape. Place a 12-inch level horizontally on the roof, measure the vertical distance from the roof to the end of the level, and that gives you the rise. The measurement method will give you the pitch in X:12 format.
What roof pitch is best for snow?
For areas with heavy snowfall, a steeper pitch of 9:12 or greater is recommended. Steeper roofs allow snow to slide off more easily, reducing the risk of snow load damage and ice dams. A minimum pitch of 6:12 is often recommended for snowy climates.
Does roof pitch affect cost?
Yes, steeper roofs generally cost more to build and maintain. They require more materials (longer rafters and more roofing material), more labor time, and additional safety equipment. However, they often provide better drainage and longer-lasting protection.
Can I walk on a steep pitch roof?
Walking on roofs steeper than 6:12 can be dangerous and typically requires special safety equipment like roof jacks, scaffolding, or fall protection harnesses. Roofs steeper than 9:12 are considered very steep and should only be accessed by professionals with proper equipment.