Metal Roofing Panel Calculator
Count panels the way the supplier cuts them: the eave-to-eave width of one roof plane divided by the coverage width of your panel profile, rounded up, times the panel length from eave to ridge. Coverage width is the net width a panel actually covers after the side lap — 36 inches for common exposed-fastener profiles, 24 or 16 for many standing seam profiles — and it comes off the profile spec sheet, not a guess. Free, no login.
Roof / Panels
Panels
Panels = ceil(width ÷ coverage) from your panel profile spec; double for both roof planes. Add trim, ridge, and closures.
Metal Roof Panels — Material Order Sheet
Prepared with NORDIX — nordixhq.com/tools/metal-roof-panel-calculator
Roof width: 40 ft (one plane) · Panel coverage: 36 in · Panel length: 16 ft
| Line item | Quantity | Notes |
|---|---|---|
| Panels @ 16 ft | 14 panels | One plane: ceil(40 ft × 12 ÷ 36" coverage) |
| Total panel lineal feet | 224 lf | One plane — double for both roof planes |
Counts are per roof plane from the user-entered panel coverage width (profile spec). Verify panel length against the true slope (rafter) length, and add trim, ridge cap, closures, fasteners, and sealant separately — none are included in the panel count.
How this calculator works
panels = ⌈roof width (ft) × 12 ÷ coverage (in)⌉ · lineal ft = panels × panel length
This is pure geometry on the coverage width you enter — the calculator carries no built-in panel table because coverage is a property of the specific profile, and the spec sheet governs. Two things matter for accuracy: use the net coverage width (after side lap), not the overall sheet width, and use the sloped (rafter) length for the panel length, not the plan depth — a 14 ft plan run at 6/12 needs 15.65 ft panels. The count is per plane; a gable roof doubles it.
Worked example
One plane of a 40 ft wide roof in a 36"-coverage panel, 16 ft eave-to-ridge:
- Panels: 40 × 12 = 480" ÷ 36" = 13.3 → 14 panels (the last one gets ripped).
- Lineal feet: 14 × 16 = 224 lf of panel for this plane.
- Both planes of a symmetric gable: 28 panels, 448 lf — plus trim, ridge, closures, and fasteners as separate lines.
Enter the same plane above (40 ft, 36", 16 ft) to reproduce it.
Reference: panels per plane by width and coverage
Computed by the same engine — panel counts for one roof plane at three common coverage widths. Your profile’s spec sheet sets the real coverage; partial panels count as whole panels.
| Plane width | 36" coverage | 24" coverage | 16" coverage |
|---|---|---|---|
| 20 ft | 7 | 10 | 15 |
| 30 ft | 10 | 15 | 23 |
| 40 ft | 14 | 20 | 30 |
| 50 ft | 17 | 25 | 38 |
| 60 ft | 20 | 30 | 45 |
Frequently asked questions
How do I calculate how many metal roofing panels I need?
Convert the roof width (eave to eave along one plane) to inches, divide by the panel's net coverage width, and round up — that's the panel count for that plane, which is exactly what this calculator does. Panel length is the eave-to-ridge slope distance including overhang, and lineal feet is simply panels × length. Run each roof plane separately; for a symmetric gable you can double one plane's result.
What is panel coverage width, and why isn't it the panel's actual width?
Coverage (net) width is the width a panel actually covers after the side lap or seam engages the next panel — a common exposed-fastener panel with 36-inch coverage is closer to 38–39 inches of raw sheet. Always use the coverage width from the manufacturer's spec sheet in this calculator; using the overall sheet width undercounts panels. Typical coverages: 36 in for corrugated and PBR/R-panel, and 12–24 in (16 in is common) for standing seam.
How long should my metal roof panels be?
Eave to ridge along the slope, plus eave overhang — take the horizontal run and multiply by the slope factor (√(1 + (rise/12)²)) to get the slope length. Most suppliers cut panels to length, and a single full-length panel with no end lap is the goal. If the slope is longer than the maximum shippable panel, you'll need end laps — commonly 6 inches or more, laid per the manufacturer — so add that to the lineal footage.
Does the panel count cover the whole roof or one side?
One plane. The width input is eave-to-eave across a single plane, so a plain gable is this result × 2, and a hip or multi-plane roof should be figured plane by plane at each plane's widest point. Trapezoidal hip planes cut from full-width panels generate offcuts you usually can't reuse, so expect real waste there even though the count math is exact.
What else do I need besides the panels?
Trim and accessories are a separate takeoff this calculator doesn't include: ridge cap, eave/drip edge, rake (gable) trim, sidewall and endwall flashing, and foam closure strips at ridge and eave. Add fasteners per the manufacturer's pattern (screw counts vary by panel profile and wind zone) plus underlayment. On a metal job the trim package is a meaningful share of the material cost, so don't price panels alone.
Method: panels = plane width ÷ panel net coverage width, rounded up; lineal feet = count × panel length. Pure geometry on user-entered values with no built-in product table — the panel profile spec governs coverage width, and panel length must be the sloped (rafter) length including any eave overhang the profile details call for. The count excludes trim, ridge cap, Z-closures, sealant, and fasteners, and it does not add waste for hips, valleys, or dormers, where diagonal cuts consume extra panel — take those off separately.
Pair with the Roof Pitch Multiplier to get the sloped panel length from a plan dimension, or the Roof Area & Pitch Calculator for the total surface when you are comparing metal against shingles by the square.