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Roofing Calculator

A materials estimator for simple gable or hip roofs. It takes plan-view length and width plus pitch to compute surface area, roofing squares (100 sq ft), and a bundle count using a waste factor. It does not pull aerial measurements or contractor pricing.

Footprint along the eaves, not the slope length.

Footprint from eave to eave, plan view.

Common pitches are rise over a 12-inch run. Choose Custom to type another rise and run.

Default 10% for hips, valleys, starter, and cuts.

Inches of rise. 6 in a 6/12 pitch.

Inches of run. Usually 12.

Asphalt shingles are commonly 3 bundles per square. Check the product spec.

Roofing estimate

Plan area
1,200 sq ft
Pitch factor (6/12)
1.118
Surface area
1,341.64 sq ft
Roofing squares
13.42
Estimated bundles
45

Materials estimate only, not a bid. Pitch factor is √(1 + (rise ÷ run)²). One square is 100 sq ft of roof surface. Bundles round up after the waste factor and do not include flashing or underlayment. Labor, tear-off, and local prices vary — get a contractor bid for cost.

Frequently asked questions

What is a roofing square?

One square is 100 square feet of roof surface.

How does pitch change area?

Steeper roofs have more surface than the footprint. The tool multiplies plan area by a pitch factor (rise/run).

How many bundles per square?

Asphalt shingles are commonly 3 bundles per square. Check the product spec.

Does this include flashing and underlayment?

No. It estimates field shingles/area only. Add waste for hips, valleys, and starter.

Is this a replacement quote?

No. Labor, tear-off, and local prices vary. Get a contractor bid for cost.

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