Metal Roofing Calculator
Calculate metal roof panels, screws or standing-seam clips, and eave, rake, ridge, and hip trim from your roof area and linear dimensions. Exposed-fastener or standing seam.
Exposed-fastener uses face screws; standing seam uses concealed clips — very different fastening.
Net, after overlap.
Sum across all planes; split evenly below.
Panels are rounded up per plane, then summed.
For rake trim takeoff.
10% gable, 15%+ complex/hip.
Metal roof takeoff
36" coverage, cut to 20 ft, across 2 planes
~80 per square (varies by profile).
Eave + rake + ridge + hip/valley, with waste.
- Eave trim
- 80 ft
- Rake trim
- 40 ft
- Ridge cap
- 40 ft
- Roof area
- 2,000sq ft
- Squares
- 20
- Waste applied
- 10%
Exposed-fastener panels use ~80 screws per square; standing seam uses concealed clips along the seams — very different fastening.
Order panels cut to your eave-to-ridge length to minimize end laps. Measure each roof plane.
Panels are rounded up per plane (they can’t span planes), then summed. The eave length is split evenly across the planes you set — for very unequal planes, run each plane separately and add the results.
Add 10% waste for a simple gable; 15%+ for hip roofs and complex layouts (more cuts).
Standing seam requires specific clips, sealant, and a mechanical or snap seam — confirm the system and exact clip spacing with your supplier.
Verify panel coverage width — it's the NET coverage after overlap, not the total panel width.
How this calculator works
This metal roofing calculator turns your roof area and linear measurements into a panel, fastener, and trim takeoff for both major systems — exposed-fastener and standing seam. Because the two fasten in completely different ways, the calculator switches its math: screws for exposed-fastener panels, concealed clips for standing seam. Never apply screw-per-square math to a standing-seam roof.
Panels, by plane
Panels run vertically from eave to ridge, sitting side by side across the roof. The number across is the total eave length divided by each panel's net coverage width, rounded up per plane, with waste added. Each panel is cut to the slope length so there are no end laps. Standing seam's narrower 16–18 inch coverage means more panels than 36 inch exposed-fastener for the same roof.
Fasteners: screws vs. clips
Exposed-fastener panels are face-screwed, roughly 80 screws per square once you count field, lap, and trim fasteners. Standing seam hides clips beneath the seams: the calculator estimates one clip per spacing interval along every seam, so tighter clip spacing and longer slopes both raise the count. Clip spacing is set by the manufacturer's engineered system — treat the estimate as a starting point and confirm it.
Trim is where jobs come up short
Eave, rake, ridge, and hip/valley trim are easy to under-order. The calculator takes each off your linear dimensions, adds waste for overlaps, and totals them, while still breaking out each location so you can order the right profiles. Verify net coverage width with your supplier — it is the covered width after overlap, not the physical panel width — and confirm the clip and sealant system for standing seam before ordering.
Frequently asked questions
- How many metal roofing panels do I need?
- Divide the total eave length of each roof plane by the panel's net coverage width and round up — that is how many panels run side by side. Each panel is cut to the eave-to-ridge slope length. Add 10% waste for a simple gable, more for hips and cut-up roofs. The calculator does this from your eave length and coverage width.
- How many screws per square for metal roofing?
- A common rule of thumb for exposed-fastener panels is about 80 screws per square (100 sq ft), which covers field, lap, and trim fasteners. It varies with panel profile and screw spacing — high-rib ag panel at 12-inch field spacing uses fewer than tight patterns. Standing seam does not use this math at all; it uses concealed clips.
- What's the difference between exposed-fastener and standing seam?
- Exposed-fastener panels (ag panel, R-panel, corrugated) are screwed straight through the face into the deck or purlins — fast and economical, but the rubber-washered screws are visible and eventually need re-torquing. Standing seam panels hide concealed clips under raised, seamed ribs, so nothing penetrates the weather surface; it costs more and installs slower but lasts longer and looks cleaner.
- What is "coverage width" versus panel width?
- Panels overlap at the edges, so the width they actually cover on the roof is less than the physical panel width. That covered width is the net coverage — typically 36 inches for exposed-fastener panels and 16 to 18 inches for standing seam. Always size panel counts from net coverage, never the total panel width, or you will come up short.
- How much trim do I need?
- Trim is taken off the roof's linear dimensions: eave trim equals total eave length, rake trim equals total rake length, ridge cap equals ridge length, and hip/valley flashing equals hip plus valley length. Add about 10% for overlaps and cuts. The calculator totals these for you and breaks them out by location.
- How much waste should I add for metal roofing?
- Plan on roughly 10% for a simple gable roof and 15% or more for hip roofs and complex layouts with lots of cuts. Ordering panels cut to your exact eave-to-ridge length keeps waste down because it eliminates end laps. Trim and flashing also carry about 10% for overlaps.