Construction & Exterior

Roof Shingle Calculator

Estimate simple gable roof area, roofing squares, shingle bundles, underlayment rolls, ridge cap bundles, and material cost.

Calculate roof shingles

Estimate roof area, roofing squares, bundles, underlayment, ridge cap, and material cost.

Results

Roof area

1,220.89 sq ft

Slope factor 1.118

Waste-adjusted area

1,342.98 sq ft

Roofing squares

13.43 squares

Bundles to buy

41

1,366.67 sq ft bundle coverage

Estimated shingles

861

Underlayment rolls

4

Ridge cap bundles

2

42 ft ridge

Estimated material cost

$2,062.00

How to measure roof shingles

For a simple gable roof, enter building length, building width, overhang, and roof pitch rise per 12 inches of run. For an existing takeoff or roof plan, use known roof area.

Method

Projected area = (length + 2 x overhang) x (width + 2 x overhang)
Slope factor = square root of (1 + (rise / 12)^2)
Roof area = projected area x slope factor
Roofing squares = waste-adjusted roof area / 100
Bundles = roofing squares x bundles per square, rounded up

Assumptions

  • One roofing square equals 100 square feet.
  • Bundle count is based on the user-entered bundles per square.
  • Gable mode models one simple continuous ridge.
  • Starter, hip and ridge products, valleys, flashing, drip edge, underlayment type, ice barrier, nails, and disposal are separate unless entered as optional fields.
  • Complex roofs should use a measured roof takeoff.

FAQs

Why can bundles per square change?

Many common shingles use 3 bundles per square, but products vary. Some specialty shingles use more bundles per square or different bundle coverage.

Does this handle hips, valleys, dormers, or complex roofs?

No. The gable mode is a simple planning model. Use known roof area or a professional roof takeoff for complex roofs.

Is this a roofing installation plan?

No. Flashing, drip edge, starter shingles, ice barrier, ventilation, fasteners, code, and safety planning are separate.

References

Product specifications were checked against manufacturer and retail listings showing bundle coverage and bundle-per-square variation, including Owens Corning shingle specifications and GAF Timberline HDZ product literature.