Roof area calculator
Type the ground area under the roof (overhangs included) and the pitch: you get the roof area, the margin and the number of tiles or slates.
Result
127.02 m²Area to cover with the margin
- Real roof area
- 115.47 m²
- Pitch factor
- 1.1547
- Angle
- 30°
- Slope in %
- 57.74 %
- Tiles or slates to buy
- 1,271
Inputs
- Ground area under the roof
- 100
- Pitch given in
- Degrees (°)
- Pitch
- 30
- Margin (cuts, overlaps)
- 10
- Tiles or slates per m² (optional)
- 10
How it is calculated
If every plane has the same pitch, roof area = ground area ÷ cos(angle). This holds for gable and hip roofs alike.
Result
Area to cover with the margin
- Real roof area
- 115.47 m²
- Pitch factor
- 1.1547
- Angle
- 30°
How it is calculated
- If every plane has the same pitch, roof area = ground area ÷ cos(angle). This holds for gable and hip roofs alike.
- Slope in % = tan(angle) × 100. Example: 100 % = 45°.
- Number of tiles = area with margin × tiles per m², rounded up.
Example
100 m² of ground, 30° pitch: factor 1.1547, roof of 115.47 m², 127.02 m² with a 10 % margin, so 1,271 tiles at 10 per m².
Good to know
- Planes with different pitches, dormers and valleys must be added separately.
- The number of tiles per m² depends on the model and its exposure: see the maker’s data sheet.
- Pitch limited to 80°.
Sources
- Basic trigonometry (projection of an inclined plane)
Frequently asked questions
What is this tool used for?
Type the ground area under the roof (overhangs included) and the pitch: you get the roof area, the margin and the number of tiles or slates.
How is the result calculated?
If every plane has the same pitch, roof area = ground area ÷ cos(angle). This holds for gable and hip roofs alike.
What should I check before using the result?
Planes with different pitches, dormers and valleys must be added separately.