Pitch
6:12
26.57 degrees roof angle
Free roofing tool
Free Roof Pitch Calculator
A roof pitch calculator converts rise and run into roof slope, angle, rafter length, and material area. Use it to plan roof framing, compare pitches, estimate surface area, and build a practical shingle bundle count before you buy materials.
Roof inputs
Estimate one simple roof plane group at a time.
Rafter length
20.12 ft
1.12 pitch multiplier
Material area
1,770.97 sq ft
10% waste included
Bundle cost
$2,268
54 bundles to buy
Roof pitch takeoff
Pitch ratio
6 inches of rise for every 12 inches of run
6:12
Pitch angle
50% slope
26.57 degrees
Rafter length
18 ft horizontal run multiplied by pitch factor
20.12 ft
Roof surface area
2 roof sides before waste
1,609.97 sq ft
Planning notes
- Use a 1.12 pitch multiplier for quick material takeoffs on this roof.
- Plan for about 1,770.97 sq ft of material after 10% waste.
- At 33.3 sq ft per bundle, buy 54 bundles for about $2,268 before tax or delivery.
How to use the roof pitch calculator
- 1
Enter rise and run
Add the vertical rise and horizontal run in inches, such as 6 inches of rise over 12 inches of run.
- 2
Add roof dimensions
Enter the horizontal roof run, ridge length, and number of roof sides you want to estimate.
- 3
Set waste and bundle assumptions
Choose the waste allowance, bundle coverage, and bundle price that match your roofing material.
- 4
Review pitch and material results
Use the ratio, angle, slope percent, rafter length, area, bundle count, and estimated cost for planning.
- 5
Confirm complex roof details
Add extra waste or get a pro takeoff for hips, valleys, dormers, skylights, and low-slope product requirements.
Roof pitch calculator FAQ
How do you calculate roof pitch?
Roof pitch is rise divided by run. A 6:12 pitch means the roof rises 6 inches for every 12 inches of horizontal run.
How do you convert roof pitch to degrees?
Divide rise by run, take the arctangent, then convert radians to degrees. A 6:12 pitch is about 26.57 degrees.
How do you estimate roof surface area from pitch?
Multiply horizontal roof run by the pitch multiplier, then multiply by ridge length and the number of roof sides.
How much roofing waste should I add?
A simple gable roof often uses 10% waste. Complex roofs with hips, valleys, dormers, skylights, or many cuts may need 15% or more.
How many square feet does a shingle bundle cover?
Many asphalt shingle bundles cover about 33.3 square feet, or three bundles per roofing square. Always check the actual product label.
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