roofing
Roof bundles
Slope-adjusted roof area and bundle counts with ventilation waste.
Results are approximate. Verify with manufacturer specifications or consult a professional.
Project inputs
IMPERIAL
Enter a value in ft.
Enter a value in ft.
Enter a value in °.
Enter a value in ft².
Includes breakage, spillage, onsite adjustments
Material output
Updates instantly as you type.
Primary output
1,238.1m²
1,238.1 m²
≈ 1,157.1 m² primary output
Estimated packaging
38 bundles
You need 1,238.1 m², approximately 38 bundles
Bundles
Your units
38 ea
Results are approximate. Verify with manufacturer specifications or consult a professional.
How it works
Frequently asked questions
Country defaults
United States · USD · imperial
Waste factor: 7.0%
Context & guidance
Results are approximate. Verify with manufacturer specifications or consult a professional.
About This Calculator
Calculate the exact amount of roofing materials needed for your project, including shingles, tiles, metal sheets, or membrane. Accounts for roof area, pitch/slope, waste factors (typically 10-15% for simple roofs, 15-20% for complex roofs with valleys and hips), and country-specific material standards. Supports both metric and imperial units.
Step-by-Step Instructions
Measure Roof Dimensions
Measure the length and width of each roof plane. For gable roofs, measure the building length and rafter length (from eave to ridge). For hip roofs, measure each plane separately. Use a tape measure on the ground and calculate based on building footprint if safe access isn't available.
Calculate Roof Area
For simple gable roofs: Area = Building Length × Rafter Length × 2 (both sides). For hip roofs, calculate each plane separately and sum. Account for roof pitch: steeper roofs have more surface area. The calculator applies pitch multipliers automatically.
Account for Roof Pitch
Roof pitch affects material needs. A 4:12 pitch (18.4°) increases area by ~8% vs flat. A 6:12 pitch (26.6°) increases by ~12%. A 12:12 pitch (45°) increases by ~41%. Enter pitch ratio (rise:run) or angle, and the calculator adjusts area accordingly.
Add Waste Factor
Simple roofs (gable, hip) need 10-15% waste for cuts and starter/ridge caps. Complex roofs (valleys, dormers, multiple angles) need 15-20% waste. Steeper pitches (>8:12) may need 5% extra due to increased cutting.
Select Material Type
Different materials have different coverage: asphalt shingles (3 bundles per 100 ft²), metal panels (varies by width), tiles (varies by size), membrane (roll coverage). The calculator accounts for material-specific coverage and packaging.
Calculate and Order
The calculator shows total roof area, material needed (including waste), and number of bundles/rolls/sheets required. Always round up to full packages. Order 5-10% extra for future repairs and to ensure batch matching.
Common Mistakes
Not accounting for roof pitch
Steeper roofs have significantly more surface area than flat roofs. A 12:12 pitch has 41% more area than flat. Always enter pitch ratio or angle. If unsure, use a pitch finder tool or consult building plans.
Forgetting valleys, hips, and dormers
Complex roof features (valleys where two planes meet, hips, dormers) require extra material and increase waste to 15-20%. Measure these areas separately and add to total, or use the complex roof waste factor.
Not ordering starter and ridge caps separately
Starter strips (along eaves) and ridge caps (along peak) are calculated separately from field shingles. Measure linear feet/meters of eave and ridge, then calculate based on material coverage per linear unit.
Underestimating waste for complex roofs
Simple gable roofs need 10-15% waste. Roofs with valleys, multiple angles, or dormers need 15-20% waste. Steeper pitches (>8:12) may need 5% extra. Always use the higher waste factor for complex roofs.
Pro Tips
Measure roof from the ground using building footprint and pitch. Use a pitch finder app or measure rise:run ratio. Never guess pitch—it significantly affects material needs.
For complex roofs, break into simple shapes (rectangles, triangles) and calculate each separately. Sum the totals and add 15-20% waste for the entire roof.
Order starter strips and ridge caps separately. Measure linear feet/meters of eave and ridge. Standard coverage: 1 bundle covers ~33 linear feet of eave or ridge.
Buy all shingles from the same batch/lot. Color variations between batches are noticeable, especially with architectural shingles. Order 5-10% extra for future repairs.
For metal roofing, account for panel width and overlap. Standard panels are 12-16 inches wide with 1-2 inch overlap. Calculate based on effective coverage width, not panel width.
Coordinate with your roofer on waste factors. Professional roofers may use different waste factors based on experience with your specific roof type and material.
Frequently Asked Questions
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