Roofing Calculator
Get your pitch-corrected roof area in m² and squares, the number of tiles, and the cost — from your plan dimensions and roof pitch. Free, instant, no sign-up.
Roof plan
Tiles & price
Your roofing estimate
Pitched roof area86,6 m²
Roofing squares9,3 sq
Tiles to buy (incl. waste)953 tiles
Estimated tile costR 11 436
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Create a free account →How the roofing calculation works
pitch factor = 1 ÷ cos(pitch°) roof area (m²) = plan length × plan width × pitch factor squares = roof area ÷ 9.29 tiles = ⌈roof area × tiles_per_m² × (1 + waste%)⌉
FAQ
- How do I calculate roof area from the plan?
- A pitched roof is larger than its footprint. Multiply the plan (footprint) area by the pitch correction factor 1 ÷ cos(pitch angle). This calculator applies that automatically and also converts to roofing squares.
- What is a roofing square?
- A roofing square equals 100 square feet (9.29 m²). Roofers quote and order material by the square, so a 150 m² roof is about 16 squares.
- How many tiles do I need per square metre?
- Concrete roof tiles run around 10 per m²; larger profiles fewer, slates many more. Check the tile’s stated cover — the default here is 10 per m², and a 10% waste allowance is included.
- Does this cover battens, underlay, and ridge tiles?
- No — this estimates the main roof covering. Create a free BuilderBuddi account to build the full roofing estimate with battens, underlay, ridging, flashing, and labour.
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