About this calculator
Count metal roof panels such as R-panel, PBR or corrugated, with ridge, verge and eaves trim, foam closures and screws.
How it’s calculated
Panels per side = ceil(eaves length ÷ coverage width). Panel length = slope length + eaves projection. Screws are estimated at about 80 per 100 sq ft.
Worked example
With these inputs:
- Roof length along eaves
- 40 ft
- Slope length (eaves to ridge)
- 16 ft
- Roof sides
- Two (gable)
- Panel coverage width
- 36 in
- Extra length at eaves
- 2 in
the result is:
- Panels needed
- 28 panels
- Panels per side
- 14
- Sheet area
- 1,358 sq ft
Tips from the trade
- Use the panel’s coverage width, not its overall width. Side laps eat 2–4 inches or 50–100 mm.
- Order panels cut to length. Long panels may need an end lap; check the maker’s minimum overlap for your pitch.
- Fix through the high rib or the flat depending on the profile, following the manufacturer.
Results are estimates for planning and pricing. Check quantities against your drawings, the manufacturer’s data and local building codes before ordering.