Roofing calculator
Estimate outputs: Area, Roof panels. Adjust Length, Width, Roof pitch to match your project.
Estimate outputs: Area, Roof panels. Adjust Length, Width, Roof pitch to match your project.
Inputs and units
Use the units shown beside each field. Replace the sample values with your measurements and the figures on the selected product packaging.
| Parameter | Example input |
|---|---|
| Length | 10 m |
| Width | 6 m |
| Roof pitch | 30 ° |
| Coverage per panel | 1 m² |
| Waste allowance | 10 % |
Formula and assumptions
AreaLength × Width / cos(Roof pitch × π / 180) × (1 + Waste allowance / 100)
Roof panelsceil(Area / Coverage per panel)
ceil = round up; floor = round down; max = the greater value. Trigonometric angles are converted from degrees to radians.
Allowance is applied before rounding to whole packages. Whole units are rounded up; displayed decimals are rounded only for readability.
Roof calculations assume a simple rectangular surface or equal pitch slopes. Include overhangs in the entered plan dimensions; check overlaps and effective coverage.
Worked example
Sample values are examples, not product specifications. Run the calculation again with your own measurements.
| Result | Calculation |
|---|---|
| Area | 76.2102 m² |
| Roof panels | 77 |
Related calculators
Related tools use separate measurements. Check their inputs before transferring quantities.
These are quantity estimates. Confirm product coverage, site conditions and required dimensions before ordering.