Shingle Calculator
Calculate asphalt shingle quantities from roof area. Get bundles, squares, and underlayment with waste allowance. Imperial and metric. Free, no signup.
Roof Area Calculator
Calculate actual roof surface area from plan dimensions and pitch
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Shingles — did you know?
What is a "square" of shingles?
One square covers 100 square feet. Most architectural shingles come 3 bundles per square (33.3 sq ft per bundle). Some premium brands are 4 bundles per square.
Waste percentage for shingles
Straight cuts: 10-12%. Diagonal/herringbone: 15-20%. Valleys, hips, and dormers add 2-3 bundles each. Starter strip: 1 bundle per 40 linear feet of eaves. Ridge cap: 1 bundle per 35 linear feet.
Underlayment calculation
Felt underlayment: 1 roll (400 sq ft) per 4 squares. Synthetic underlayment: 1 roll (1000 sq ft) per 10 squares. Ice & water shield: required at eaves in cold climates — 2 rows minimum.
Nail quantities
Standard 4-nail pattern: ~320 nails per square. 6-nail pattern (high wind): ~480 per square. 1 box (5,000 nails) covers ~15 squares at 4-nail or ~10 squares at 6-nail.
Formulas used
Squares needed
squares = ceil(roof_area_sqft ÷ 100 × (1 + waste%))
Bundles
bundles = squares × 3 (standard)
Starter strips
starter = ceil(eaves_length_ft ÷ 40)
Ridge caps
ridge = ceil(ridge_length_ft ÷ 35)
Frequently asked questions
How many bundles of shingles do I need?
Roof area in sq ft ÷ 100 × (1 + waste) × 3 bundles/square. 1,500 sq ft at 12% waste: 15 × 1.12 = 16.8 → 17 squares → 51 bundles.
What is a square of shingles?
One square = 100 sq ft of coverage. Most architectural shingles = 3 bundles per square. Check packaging — some premium brands are 4 bundles.
How much waste for shingles?
10-12% for straight cuts, 15-20% for diagonal patterns. Add 2-3 bundles per valley/hip/dormer for cuts.
Best free shingle calculator?
One that calculates bundles, squares, starter, ridge, and underlayment. This tool does all, free.