Metal Roofing Panel Calculator — ft to panels, screws, cost
How to use this calculator
Enter your footprint length × width plus pitch (or paste a measured roof area), pick the panel profile and length, and the output gives the exact panel count, ridge cap pieces, eave/rake trim, and screw boxes you take to the supplier. Pitch factor scales the plan area to the true slope so a 24×40 footprint at 6/12 yields 1073 ft², not 960.
Panel types — Standing seam (16–18″ coverage), Corrugated (26″ coverage), R-Panel/PBR (36″ coverage).
Pitch adjustment — When entering footprint dimensions, the calculator applies the pitch multiplier to get true roof area.
Cost — Enter price per panel or per linear foot for a full material estimate.
Saved Calculations
| Time | Type | Area ft² | Panels | Ridge | Trim | Screws | Total $ |
|---|
How to Calculate Metal Roofing Panels
Pick the panel profile first — it sets the coverage width that drives panel count. Standing seam covers 16″ or 18″ net after the seam is rolled, corrugated covers 26″, and R-panel/PBR covers 36″ after the side lap is nested. Enter the roof either as a measured surface area or as plan length × width with a rafter pitch; in plan mode the pitch factor scales the footprint up to the true slope area. Order panels to the full eave-to-ridge run when the run is under ~24 ft to avoid endlaps and leak paths; only add an endlap row when the run exceeds available panel lengths.
Defaults assume a simple gable: 10% waste covers ridge/eave trimming and a few miscut ribs. Use 5% on a clean rectangular shed and 15% on hip roofs or anything with valleys, dormers, or skylights. Screws are estimated at 80 per roofing square — fasteners land in every flat at eave and ridge and every other flat in the field for exposed-fastener panels; standing seam uses concealed clips, so the screw figure is a conservative upper bound there.
How to use
Switch the input tab to L × W + Pitch for a footprint, or Direct Area if you already have a measured roof surface from the roof area and pitch calculator. Choose your panel and length, set the endlap if panels are shorter than the run, then open the cost panel for a material total. For asphalt comparison runs see the shingle bundle calculator, and for low-slope sections the flat roof membrane calculator.
Formulas Used
Pitch factor = √(1 + (rise/12)²). Actual roof area = footprint length × width × pitch factor × number of sides. Panels across = ⌈roof width ÷ panel coverage width⌉. Rows lengthwise = ⌈slope length ÷ (panel length − endlap)⌉ when panels are shorter than the run. Ridge cap = ⌈ridge length ÷ 9.5 ft⌉ (10 ft pieces with 6″ lap). Trim = (2 × eave + 2 × rake) ÷ 10 ft. Screws ≈ 80 per roofing square (100 ft²), then × waste factor.
FAQ
How many screws per panel? Roughly 60–80 screws per 100 ft² (one roofing square). Exposed-fastener panels are screwed at every flat on eave/ridge rows and every other flat in the field; trim and closures add more.
What endlap do I need? Side lap is already inside the panel coverage width. End lap (endlap) is typically 6″ for standard pitch and 9–12″ with sealant tape for low slope below 3:12.
What else will I need to budget? Add closures, butyl tape, pipe boots, and gutters — size those with the gutter and downspout calculator, and any framing with the board feet lumber calculator or deck framing calculator for a porch addition.
On install day
Metal roofing in 2025 USA runs roughly $4–7/ft² installed for 29-ga exposed-fastener panels, $9–14/ft² for 24-ga standing seam — material alone is about half that. The single most-missed line item is trim and flashing: drip edge, sidewall flashing, valley metal, pipe boots and ridge closure strips can add 15–25% to a sheet-only takeoff, so order all of it with the panels rather than chasing pieces mid-job. Per IRC R905.10 metal roofing needs minimum 3:12 slope (or sealed laps below that), and self-adhered ice-and-water shield is required at eaves in climate zones 5 and colder. Square panels to the eave before fastening the first sheet — a 1/4″ run-out across 24 ft turns into a 1″ gap at the rake.
