Roofing Shingle Calculator
Calculate how many shingle bundles, ridge cap, and underlayment you need for your roof.
Enter dimensions and pitch for accurate material estimates.
Materials Needed
Shingle Calculator estimates roofing materials based on roof dimensions and pitch.
Roof Area = Length × Width × Pitch Multiplier
Bundles Needed = (Roof Area / 100) × 3 + 10% waste
One “square” = 100 sq ft of roof area. Most shingle bundles cover ⅓ of a square (33.3 sq ft), so you need 3 bundles per square.
Pitch multipliers:
- 3/12 (low): 1.03
- 4/12: 1.05
- 6/12: 1.12
- 8/12: 1.20
- 10/12: 1.30
- 12/12 (steep): 1.41
Additional materials per square:
- Underlayment: ~1 roll per 4 squares (covers 400 sq ft)
- Ridge cap: ~1 bundle per 35 linear feet of ridge
- Starter strip: perimeter of roof
- Nails: ~2 lbs per square
Always add 10–15% for waste, especially on complex roofs with valleys and hips.