Estimate roof area, roofing squares, and shingle bundles needed.
Roof area = footprint area × roof pitch factor; squares = roof area / 100; bundles = squares × 3.
A 1,500 sq ft roof with a moderate pitch needs about 18 squares, or roughly 54 bundles of shingles.
One square equals 100 square feet of roof area, the standard unit for selling shingles.
Steeper roofs have more surface area than the footprint; a pitch factor adjusts the footprint upward.
Yes. Add 10–15% for cuts and overlaps, more for complex roofs with valleys.