Metal roofing estimate calculator
Panels for one facet: type the width along the eave, the flat run to the ridge, the pitch and the panel width. Run it once per facet.
Panel count = eave width in inches ÷ panel coverage width, rounded up. Panel length = flat run × pitch factor, plus the eave overhang.
Add the eave overhang to the panel length, usually 1 to 2 inches past the drip edge. Panel coverage width is the net width after the lap or the seam: 16 inches for most nail-fin and standing seam profiles, 36 inches for common exposed-fastener panels.
Where the calculator stops
This counts full-length panels on a rectangle. A real roof has hips, valleys, dormers and transitions, and every panel that meets one of them is a different length. The count is right; the lengths are not, and the lengths are what you order.
What All Roof Pricer does instead: it lays each panel strip across every facet, reads the length where the strip meets a hip, valley or dormer, groups the panels into a runout list by length, prints a cut list by facet, and exports the CSV a panel machine takes. The metal panel cut list page walks through it.
The rest of a metal roofing estimate
| Item | Where the number comes from |
|---|---|
| Panels | One line per length with its count, from the layout on each facet. Spares by count. |
| Trim and flashing | Lineal feet of each line type: eave, rake, ridge, hip, valley, headwall, sidewall, transition. True length on the slope, not the plan length. |
| Underlayment | Squares of roof ÷ roll coverage, with the lap waste; ice and water in the valleys and, if you choose, on the hips. |
| Accessories | Pipe boots by size, vents, skylights, chimney flashing, counted from the drawing. |
| Labor | Install per square by the product, tear-off per square, drive time by the trip. |
| Job costs | Dump fee, permit, delivery, warranty reserve, tax, markups. |
Both metal paths, standing seam and exposed fastener, are described on their own pages: estimating standing seam and estimating exposed fastener metal.
Questions
How do I calculate how many metal roofing panels I need?
Divide the width of the facet along the eave, in inches, by the panel coverage width, and round up. A 40-foot eave with 16-inch panels is 480 ÷ 16 = 30 panels. Each facet is counted on its own; a gable roof has two facets, so 60 panels.
How long should the metal panels be?
The run from the eave to the ridge measured along the slope, plus the overhang at the eave. The slope run is the flat run times the pitch factor. A 15-foot flat run at 6/12 is 15 × 1.118 = 16.77 feet, about 16 feet 9 1/4 inches, before the overhang.
What about hips and valleys?
Every panel that meets a hip or valley is cut at an angle, and its length is different from its neighbor. A hand calculation gives the full-length panel count only. All Roof Pricer lays each panel strip across the facet and reads its real length at the cut, so the runout list has one line per length with the count.
Does the calculator include waste?
No. On a gable there is little waste to add beyond the spares you want. On a hip roof or a roof with valleys the waste is the offcuts of the angled panels, which depends on the roof. The app counts the actual pieces; spares are added by count, not by a percentage.
What does a metal roofing estimate need beyond the panels?
Trim and flashing by the foot for each line type: eave drip, rake trim, ridge cap, hip cap, valley metal, sidewall and headwall flashing, transitions. Underlayment by the square with its lap waste. Screws or clips, closures, sealant, pipe boots and vents. Labor per square, tear-off, dump, permit, delivery and trips.