📐 Roof Pitch Calculator
Calculate roof pitch, angle, and area multiplier
Horizontal distance (half the building width)
Vertical distance from wall to ridge
How to Use This Calculator
Enter Run Distance
Input the run in feet. This is the horizontal distance from the outside wall to the ridge (center of roof). For a 24-foot wide building, the run is 12 feet (half the width).
Enter Rise or Pitch
Choose to enter either rise (vertical distance) or pitch (inches per 12 inches). Check the box to use pitch instead of rise. Common pitches are 4/12, 6/12, 8/12, or 12/12.
Calculate Pitch
Click "Calculate Roof Pitch" to see the roof pitch (inches per 12"), pitch angle (degrees), and roof area multiplier. The calculator converts between pitch and rise automatically.
Use Results
Use the pitch angle and area multiplier for roofing calculations. The area multiplier helps calculate actual roof surface area from the building footprint.
Formula
Pitch = (Rise ÷ Run) × 12 (inches per 12 inches)
Pitch Angle = arctan(Rise ÷ Run) (degrees)
Rise from Pitch = (Run × Pitch) ÷ 12
Roof Area Multiplier = √(1 + (Pitch/12)²)
Example 1: Standard Roof (12 ft run, 3 ft rise)
Step 1: Calculate pitch: (3 ÷ 12) × 12 = 3/12 pitch
Step 2: Calculate angle: arctan(3 ÷ 12) = arctan(0.25) = 14.0°
Step 3: Calculate area multiplier: √(1 + (3/12)²) = √(1 + 0.0625) = √1.0625 = 1.031
Example 2: Steep Roof (12 ft run, 6/12 pitch)
Step 1: Calculate rise: (12 × 6) ÷ 12 = 6 feet
Step 2: Calculate angle: arctan(6 ÷ 12) = arctan(0.5) = 26.6°
Step 3: Calculate area multiplier: √(1 + (6/12)²) = √(1 + 0.25) = √1.25 = 1.118
About Roof Pitch Calculator
The Roof Pitch Calculator is an essential tool for contractors, roofers, architects, and DIY enthusiasts who need to accurately calculate roof pitch, pitch angle, and roof area multipliers for their roofing projects. This calculator eliminates guesswork by providing precise pitch calculations and conversions between pitch (inches per 12") and angle (degrees), helping you plan roofing materials and understand roof geometry.
When to Use This Calculator
- Roof Design: Calculate roof pitch for new roof design or planning
- Roof Replacement: Verify roof pitch for replacing existing roofs
- Material Estimation: Calculate roof area multiplier to estimate roofing materials accurately
- Pitch Conversion: Convert between pitch (inches per 12") and angle (degrees)
- Building Planning: Determine appropriate roof pitch for climate and building type
Why Use Our Calculator?
- ✅ Pitch Calculations: Precise pitch calculations in inches per 12 inches
- ✅ Angle Conversion: Converts pitch to angle in degrees automatically
- ✅ Area Multiplier: Calculates roof area multiplier for accurate material estimation
- ✅ Multiple Inputs: Supports both rise and pitch inputs for convenience
- ✅ Pitch Descriptions: Provides pitch descriptions (low, moderate, steep, etc.)
- ✅ Time Savings: Instant calculations eliminate manual math and conversions
Common Applications
Residential Roofing: Homeowners and contractors planning new roofs or roof replacements use this calculator to determine roof pitch. Standard residential roofs use 6/12 pitch (6 inches rise per 12 inches run), which this calculator helps determine accurately.
Commercial Roofing: Contractors and architects planning commercial roofs use this tool to estimate roof pitch and area multipliers needed. Commercial roofs may use different pitches based on climate and building design.
Material Estimation: Roofers and contractors use this calculator to determine roof area multipliers for accurate material estimation. The area multiplier helps calculate actual roof surface area from building footprint.
Tips for Best Results
- Common Pitches: Standard pitches: 4/12 (low), 6/12 (standard), 8/12 (moderate), 12/12 (45° angle)
- Run Calculation: Run is half the building width (from wall to ridge center)
- Area Multiplier: Use area multiplier to calculate actual roof area: Footprint Area × Multiplier = Roof Area
- Pitch Selection: Steeper pitches shed water better; lower pitches are more economical
- Climate Considerations: Steeper pitches (8/12+) better for heavy snow; lower pitches (4/12) for mild climates
Frequently Asked Questions
What is a 6/12 roof pitch?
A 6/12 roof pitch means the roof rises 6 inches for every 12 inches of horizontal run. This equals a 26.6° angle and is the standard pitch for most residential roofs. It provides good water drainage while being economical to build.
What's the difference between pitch and angle?
Pitch is expressed as inches of rise per 12 inches of run (e.g., 6/12). Angle is expressed in degrees (e.g., 26.6°). They describe the same roof slope but in different units. Pitch is more common in construction; angle is more common in geometry.
How do I calculate roof area from pitch?
Multiply the building footprint area by the roof area multiplier. For example, a 24×30 foot building (720 sq ft footprint) with 6/12 pitch (multiplier 1.118) has a roof area of 720 × 1.118 = 805 sq ft. The multiplier accounts for the roof slope.
What's a good roof pitch for snow?
Steeper pitches (8/12 or steeper) shed snow better than lower pitches. For heavy snow areas, use 8/12 or steeper. For light snow, 6/12 is usually adequate. Very low pitches (3/12 or less) may accumulate snow and require special roofing materials.
Can I use this for existing roofs?
Yes! Measure the run (horizontal distance) and rise (vertical distance) of your existing roof, then use the calculator to determine the pitch. This helps verify pitch for roof replacement or material estimation.
What's the minimum roof pitch?
Minimum roof pitch depends on roofing material: asphalt shingles require 2/12 minimum, metal roofing can go as low as 1/12, built-up roofs can be nearly flat. Check manufacturer specifications for your roofing material's minimum pitch requirements.