KORRoofing calculator
Enter the roof as measured on the plan and its pitch: the true area, the shingle bundles and the rest update as you type.
How it's calculated
- True area = length × width in plan × pitch factor. Factor = √(1 + (rise ÷ 12)²): 4/12 = × 1.054, 6/12 = × 1.118, 8/12 = × 1.202, 12/12 = × 1.414.
- Shingles = true area ÷ 100 sq. ft (1 square) × 3 bundles, + waste, rounded up.
- 4x8 sheathing = true area ÷ 32 sq. ft, + waste, rounded up. Underlayment = true area, + waste.
- Drip edge and starter strip = roof perimeter in plan, + waste. Membrane = roof perimeter × membrane width, + waste. Ridge cap = ridge length, + waste.
Measure once. The rest follows.
In KOR, this calculation happens on its own from your plans: trace the roof once on the plan, pick the pitch, and the shingles, sheathing, membrane and drip edge follow.
Try free for 14 days14-day free trial, no credit card.
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