Roofing
Roof Area Calculator
Actual roof surface area from the building footprint and pitch, for gable or hip roofs.
roof area = plan area ÷ cos(pitch)
Also called roof square meters · roof surface area
Home & Construction · 9 calculators
Roofing Calculators
Roof area, pitch, slope and angle, shingles, roofing materials and cost, rafter length, gable, hip and metal roofs.
Roofing
Roof Pitch Calculator
Convert between roof pitch in degrees, ratio, percentage and rise over run.
pitch angle = arctan(rise ÷ run)
Also called roof angle calculator · roof slope calculator
Roofing
Roofing Material Calculator
Tiles, slates or sheets needed for a roof, with battens, underlay and ridge tiles.
units = roof area × (1 + waste) × units p…
Also called roof tiles calculator · how many roof tiles
Roofing
Shingle Calculator
Asphalt shingle bundles and squares for a roof, with starter and ridge cap allowances.
1 square = 100 ft² = 3 bundles of standar…
Also called asphalt shingles calculator · roofing squares
Roofing
Roof Cost Calculator
Total re-roofing cost including materials, labour, stripping the old roof and scaffolding.
total = (materials + labour + stripping) …
Also called new roof cost · roof replacement cost
Roofing
Rafter Length Calculator
Common rafter length from span and pitch, including overhang, plus the hip and jack rafters.
rafter = (run + overhang) ÷ cos(pitch)
Also called rafter size calculator · common rafter length
Roofing
Gable Roof Calculator
Area, rafter length, ridge height and gable end area for a two-slope gable roof.
area = 2 × (run + overhang) ÷ cos(pitch) …
Also called gable end calculator · pitched roof calculator
Roofing
Hip Roof Calculator
Surface area, ridge length and hip rafter length for a four-slope hip roof.
area = 2 trapezoids + 2 triangles, all on…
Also called hip roof area · four slope roof
Roofing
Metal Roofing Calculator
Metal roofing sheets, screws and flashing for a roof, allowing for side and end laps.
sheets across = roof width ÷ (sheet width…
Also called metal roof sheets · corrugated sheet calculator
Key roofing formulas
| Roof Area | roof area = plan area ÷ cos(pitch) |
|---|---|
| Roof Pitch | pitch angle = arctan(rise ÷ run) · multiplier = √(1 + (rise/run)²) |
| Roofing Material | units = roof area × (1 + waste) × units per m² |
| Shingle | 1 square = 100 ft² = 3 bundles of standard shingles |
| Roof Cost | total = (materials + labour + stripping) × area + scaffolding + contingency |
| Rafter Length | rafter = (run + overhang) ÷ cos(pitch) |
| Gable Roof | area = 2 × (run + overhang) ÷ cos(pitch) × length |
| Hip Roof | area = 2 trapezoids + 2 triangles, all on the slope plane |
| Metal Roofing | sheets across = roof width ÷ (sheet width − side lap) |
Roofing questions
What does a 6/12 pitch mean?
The roof rises 6 units for every 12 units of horizontal run — an angle of 26.57°.