Roof Area Calculator
Convert a roof's plan area into its true sloping area from the pitch angle, for sheeting and tile estimates. Enter roof plan length, roof plan width…
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Convert a roof's plan area into its true sloping area from the pitch angle, for sheeting and tile estimates. Enter roof plan length, roof plan width and pitch to see plan area and sloping roof area when you calculate.
Worked example
Example calculated from the starting values. Enter your own values and press Calculate to get your result.
With the default inputs (roof plan length = 12 m, roof plan width = 8 m, pitch = 22.5 degrees), the results are: plan area 96.0 m²; sloping roof area 103.9 m².
Quick reference: roof plan length vs result
Reference table based on the example values; it is not your calculation result.
| Roof plan length (m) | Plan area | Sloping roof area |
|---|---|---|
| 6 | 48.0 m² | 52.0 m² |
| 12 | 96.0 m² | 103.9 m² |
| 24 | 192.0 m² | 207.8 m² |
| 60 | 480.0 m² | 519.5 m² |
| 120 | 960.0 m² | 1,039.1 m² |
| 240 | 1,920.0 m² | 2,078.2 m² |
Frequently asked questions
What formula does this calculator use?
Plan area = l × w; Sloping roof area = l × w ÷ cos(p × pi ÷ 180). Variables: l = roof plan length in m, w = roof plan width in m, p = pitch in degrees.
What do I need to enter?
You need roof plan length (m), roof plan width (m), pitch (degrees). Results update as you type.
What is an example result?
With the default inputs (roof plan length = 12 m, roof plan width = 8 m, pitch = 22.5 degrees), the results are: plan area 96.0 m²; sloping roof area 103.9 m².
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