Metal Roof Calculator

How Metal Roof Panels Are Counted

Unlike shingles (counted by bundles per square), metal panels are counted per column: each panel runs from eave to ridge at your slope length, and the number of columns is your eave length divided by the panel's net coverage width — the exposed width after the side lap or seam. The formula:

• Panels per slope = ceil(Eave length × 12 ÷ Net coverage width in inches)
• Panel length = slope length = (half width + overhang) × pitch multiplier
• Total panels = ceil(panels per slope × number of slopes × (1 + waste))

Coverage presets (p2-data-2)

• Standing seam: 16" net coverage, hidden clips (≈0.5/sq ft)
• 5V crimp: 24" net coverage, exposed screws
• R-panel / PBR: 36" net coverage, exposed screws
• Corrugated 2.5": 34.5" net coverage, exposed screws

Exposed-fastener screws are estimated at ≈1 per sq ft of covered area; standing seam clips at ≈0.5 per sq ft. Always confirm fastener spacing against the manufacturer's installation instructions.

Worked Example

A 50 × 30 gable with 1 ft overhang and 6/12 pitch: eave length 52 ft, slope length (15 + 1) × 1.118 ≈ 17.9 ft. With 5V crimp (24" coverage): 26 panels per slope → 52 panels → 58 panels with 10% waste, covering ≈ 20.9 squares. Fasteners: ≈ 2,075 screws (9 boxes); ridge: 50 ft → 6 pieces of 10 ft ridge cap.

Assumptions & Limitations

Models simple gable or shed roof shapes. Hip roofs have four eaves of different lengths — count panels per direction or add extra waste (the Roof Waste Calculator recommends 12%+). Valley/Hip trim, flashing, closure strips and underlayment are separate line items; panels are assumed factory-cut to slope length with no end laps.