Roof Pitch Calculator

A Roof Pitch Calculator helps measure how steep a roof is by showing the relationship between rise and run. Rise means how much the roof goes up vertically, while run means how far it goes horizontally. This measurement is essential for roof design, material selection, and proper water drainage.

This calculator is useful for builders, contractors, and homeowners who want clear and accurate roof slope values without doing manual calculations.

Roof pitch is commonly expressed as a pitch ratio, such as 6:12. This means the roof rises 6 inches for every 12 inches of horizontal distance. Roof slope can also be represented as an angle in degrees, which is helpful for architectural planning and detailed construction work.

Having the correct roof slope improves drainage, increases weather resistance, and helps protect the structure from water-related damage over time.

The calculator uses basic construction measurements. You enter the roof’s rise and run, and the tool applies building geometry and simple trigonometry to calculate the pitch ratio and roof angle.

This makes roof planning easier by helping with rafter sizing, roof framing, and selecting the correct roofing system for the project.

Roof pitch plays a key role in overall building performance. Steeper roofs shed water and snow more efficiently, while low-slope roofs require specialized materials and design considerations. Roof pitch also affects load distribution, material compatibility, and long-term durability. Roof pitch calculations are often combined with material planning, and full roofing estimates may include related tools like the Roof Shingle Calculator.

Roof pitch is calculated using rise and run. Rise represents the vertical height of the roof, while run represents the horizontal distance. These two measurements form the foundation of all roof pitch calculations.

The result is expressed as a pitch ratio such as 4:12 or 6:12, where the run is standardized to 12 units for easy comparison and construction reference.

• Measure the vertical rise of the roof.
• Measure the horizontal run (commonly 12 inches).
• Divide rise by run to get the pitch ratio.
• Example: Rise = 6 inches
• Run = 12 inches
• Roof Pitch = 6 ÷ 12 = 6:12

This means the roof rises 6 inches for every 12 inches of horizontal distance. This calculation method is widely used in roof framing and structural planning.

In architectural drawings and detailed roof designs, roof slope is often required in degrees instead of ratios. Trigonometry is used to convert pitch into an angle.

This conversion helps builders and designers understand roof steepness more precisely and ensures accurate measurements.

• Assume a roof with Rise = 8 inches
• Run = 12 inches
• Pitch ratio = 8:12
• Divide rise by run: 8 ÷ 12
• Angle = arctangent (8 ÷ 12)
• Roof angle ≈ 33.7 degrees

This example provides both the pitch ratio and roof angle, which are essential for planning roof structure, materials, and drainage.

The Roof Pitch Calculator automates rise and run calculations. By entering the values, the calculator instantly determines the pitch ratio and roof angle without manual effort.

This saves time, reduces calculation errors, and supports accurate roof design, rafter sizing, drainage planning, and long-term structural durability.