How to Calculate Roof Shingles
What is Roof Shingles?
A roof shingles calculator estimates the number of shingles or tiles, and the number of "squares" (100 sq ft / 9.29 m²), needed to cover a roof. It accounts for pitch, waste, and overlap.
Step-by-Step Guide
- 1Measure the footprint area of the roof from below (length × width of house)
- 2Apply pitch multiplier: 4/12 pitch = ×1.054, 6/12 = ×1.118, 8/12 = ×1.202
- 3Add 10–15% waste allowance for valleys, hips, and ridges
- 41 square = 100 sq ft; most shingle bundles cover 33 sq ft → 3 bundles per square
Worked Examples
Input
Footprint 1,200 sq ft · 6/12 pitch · 10% waste
Result
15 squares (45 bundles)
1200×1.118×1.1÷100=14.75 squares
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