Roofing Material Calculator
Calculate roofing material quantities from roof area and pitch. Enter dimensions, choose material type, and get quantities with waste allowance included. Free, no signup.
Draft Smart Component
Build a component with pricing, waste, and labour rules, then calculate cost from measurements
Component spec
Area measurement in square metres. Used for roofing, flooring, cladding.
Measurement
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Roofing materials — did you know?
How material quantities are calculated
Quantity = roof_area × (1 + waste%) ÷ coverage_per_unit. For concrete tiles at 10% waste covering 122 m²: 122 × 1.10 ÷ 0.33 (tiles per m² at ~3.3 tiles/m²) = ~407 tiles.
Coverage varies by material type
Concrete tiles: ~9-12 per m². Clay tiles: ~10-15 per m². Slate (500mm): ~20 per m². Metal sheets: calculate by sheet area minus laps. Shingles: 3 bundles per square (100 sq ft).
Why waste percentage matters
Waste covers cuts at valleys, hips, chimneys, and edges. Concrete tiles: 5-10%. Clay tiles: 10-15% (fragile). Metal sheets: 5%. Shingles: 10-15%. Add 5% extra for complex roofs.
Ordering vs calculating
Always round UP to the nearest pack/batch quantity. Suppliers often sell tiles in batches of 100, sheets in 3m lengths, shingles in bundles of ~10 m². Check supplier pack sizes before ordering.
Formulas used
Material quantity
qty = area × (1 + waste%) ÷ coverage
Roof area from plan
area = plan_area × (1 ÷ cos(pitch°))
Tiles needed
tiles = area × tiles_per_m² × (1 + waste%)
Squares (shingles)
squares = roof_area_sqft ÷ 100
Frequently asked questions
How do I calculate how many roof tiles I need?
roof_area × tiles_per_m² × (1 + waste%). For 122 m² at 10 tiles/m² and 10% waste: 122 × 10 × 1.10 = 1,342 tiles.
How many bundles of shingles do I need?
3 bundles per square (100 sq ft). For 1,500 sq ft roof at 15% waste: 15 × 1.15 = 17.25 → 18 squares → 54 bundles.
What waste percentage for roofing materials?
Concrete tiles 5-10%, clay tiles 10-15%, metal sheets 5%, shingles 10-15%. Add 5% extra for complex roofs.
Best free roofing material calculator?
One that takes roof area + pitch, applies waste, and outputs quantities per material type. This tool does all, free.