Roof Pitch Calculator

Free roof pitch calculator to convert slope, angle, and rise/run ratios. Calculate roof surface area, pitch degrees, and slope percentage. Perfect for contractors and DIY builders.

Calculate Roof Pitch

Enter rise and run, angle, or slope percentage to calculate roof pitch ratio, angle, and surface area

Length Unit

Area Unit

Method 1: Rise & Run

Rise (inches)

Run (inches)

Method 2: Angle

Angle (degrees)

Method 3: Slope %

Slope (%)

Roof Surface Area (Optional)

Projected Floor Area (sqft)

Enter the floor plan area to calculate actual roof surface area

Common Roof Pitch Examples

Key Features

Convert between pitch ratio, angle, and slope percentage

Calculate actual roof surface area from projected area

Multiple unit support (inches, feet, meters)

Common pitch examples for quick reference

Copy results to clipboard for easy sharing

Professional accuracy for construction projects

Understanding Roof Pitch

Pitch Ratio: Expressed as rise:run (e.g., 4:12), where the first number is the vertical rise and the second is the horizontal run, typically standardized to 12 inches.

Roof Angle: The angle between the roof surface and horizontal plane, measured in degrees. Steeper roofs have higher angles and better water drainage.

Slope Percentage: The rise divided by run expressed as a percentage. A 4:12 pitch equals approximately 33% slope.

Surface Area: The actual roof surface area is larger than the floor plan due to the slope. Our calculator uses the formula: Area = Projected Area × √(1 + (rise/run)²).

Tips & Best Practices

Measuring Accuracy: Use a level and measuring tape for accurate rise and run measurements. A 2-foot level is typically sufficient for most calculations.

Material Estimation: Add 10-15% extra material when ordering shingles or roofing materials to account for waste and cuts.

Safety Considerations: Steep roofs (over 6:12 pitch) require additional safety equipment and may need professional installation.

Building Codes: Check local building codes for minimum pitch requirements based on your roofing material and climate conditions.

Common Use Cases

New Construction: Calculate roof pitch for architectural plans, material estimates, and building permit applications.

Roofing Contractors: Accurate measurements for material ordering, labor estimation, and customer quotations.

Home Renovation: Planning additions, dormers, or roof modifications to match existing pitch requirements.

DIY Projects: Shed construction, gazebo roofing, and small structure planning for homeowners.

How to Use the Roof Pitch Calculator

Step-by-Step Instructions

1Select your preferred units for length (inches, feet, meters) and area measurements
2Choose one of three input methods: rise/run measurements, angle in degrees, or slope percentage
3Enter your measurements and click the Calculate button for your chosen method
4Optionally enter projected floor area to calculate actual roof surface area for material estimation
5Copy results to clipboard or use the clear function to start a new calculation

Pro Tips

For best accuracy, measure over the longest possible span to minimize measurement errors
Use a digital angle finder for direct angle measurements on existing roofs
Consider weather and wind load requirements when selecting roof pitch for new construction
Double-check calculations with manual verification for critical construction projects

Frequently Asked Questions

What is the most common roof pitch?

The most common roof pitch is 4:12, which means 4 inches of vertical rise for every 12 inches of horizontal run. This pitch provides good water drainage while being relatively easy to work on and cost-effective for most residential applications.

How do you measure roof pitch on an existing roof?

Use a level and measuring tape in the attic or on the roof surface. Place a 12-inch level horizontally, then measure vertically from the end of the level to the roof surface. This vertical measurement gives you the rise over 12 inches of run.

What roof pitch is too steep to walk on safely?

Generally, roofs steeper than 6:12 (26.6 degrees) become increasingly difficult and dangerous to walk on. Roofs over 8:12 (33.7 degrees) typically require safety equipment and professional installation. Always prioritize safety and use proper fall protection equipment.

Does roof pitch affect the amount of materials needed?

Yes, steeper roofs require more materials because the actual surface area is larger than the floor plan area. A 6:12 pitch roof requires approximately 12% more materials than the projected area, while an 8:12 pitch requires about 20% more materials.

Can I use this calculator for metric measurements?

Absolutely! Our roof pitch calculator supports both imperial (inches, feet) and metric (centimeters, meters) units. The mathematical relationships remain the same regardless of the unit system used for measurements.

What's the difference between pitch and slope?

Pitch is typically expressed as a ratio (rise:run), while slope is expressed as a percentage or decimal. Both describe the same roof characteristic but in different formats. Our calculator converts between all common formats automatically.