There are approximately 33.33 square feet in a bundle of standard composite shingles. A square is a 10-foot by 10-foot area and requires three bundles of shingles for coverage.
Before placing shingles on a roof, roofers determine the total area to be covered and divide by 100, the area of a square, to determine the total number of bundles needed to complete the job. The number of square feet in a bundle is printed on the paper or plastic packaging that covers the bundle. There are 29 standard shingles in a bundle. There are 19 sheets in a bundle of rake starter shingles.