Roof Calculator
Calculate your roof area accounting for pitch. Shows roofing squares (US/Canada) and square metres (UK/AU). Includes waste factor for shingles, tiles, or metal roofing.
| Country | Area Unit | Pitch Convention | Common Material |
|---|---|---|---|
| 🇺🇸 United States | Roofing squares (100 ft²) | x/12 (e.g., 6/12) | Asphalt shingles |
| 🇨🇦 Canada | Squares or m² | x/12 or degrees | Asphalt shingles |
| 🇬🇧 United Kingdom | Square metres (m²) | Degrees (e.g., 35°) | Clay or concrete tiles |
| 🇦🇺 Australia | Square metres (m²) | Degrees or % pitch | Metal/Colorbond, tiles |
| 🇩🇪 Germany | Square metres (m²) | Degrees (Dachneigung) | Clay tiles |
Frequently Asked Questions
What is a roofing square?
A roofing square is 100 square feet (9.29 m²). It's used only in the US and Canada. Asphalt shingles are sold in bundles — 3 bundles typically cover one square (though some heavyweight shingles require 4 bundles per square). In the UK, Australia, and the rest of the world, all roofing materials are quoted per m².
How much does roof pitch affect material cost?
A 6/12 pitch adds 11.8% more area than the footprint. A 9/12 pitch adds 25%. A 12/12 (45°) pitch adds 41.4%. Higher pitches also add labour cost because they're harder to work on safely. UK and Australian roofs are commonly steeper (35–45°) for rain runoff; US suburban homes commonly use 4/12–6/12 pitches for easier construction.