10 Minute BidsMetal roof panel calculatorPanel count, cut length and trim.
Enter one roof plane: its eave length, rafter run, pitch and overhang, and your panel's coverage width. You get the panel count, each panel's cut length and the trim pieces.
Your estimate
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| Pitch factor√(1 + (rise ÷ 12)²) | — |
|---|---|
| Slope length(run + overhang) × pitch factor | — |
| Panel cut lengthrounded up to the next ½ in | — |
| Panels per planeeave ÷ coverage, rounded up | — |
| Panels | — |
| Panel lineal feet | — |
| Roof areaeave × slope length × planes | — |
| Squares | — |
| Trim pieces | |
| Eave | — |
| Rake | — |
| Ridge | — |
How we got it
Skip the math — upload your plans. We measure it all on a 3D model of your house.
Priced per plan setMetal roofing bid, 3D model included
Upload your plansWhere hand math goes wrong: hips, valleys and dormers. Panels on those planes are cut to many lengths, and the trim list grows: hip cap, valley, sidewall and headwall flashing. Upload your plans and we cut every panel to length on a 3D model.
This is an estimate from the numbers you enter. It covers one plane at one pitch. It doesn't see the roof as it really is: rot or old layers under a re-roof, or crickets and saddles that aren't drawn. Confirm measurements on site before you order panels.
The metal panel formulas.
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Slope length
From the ridge down the slope to the eave edge.
slope length = (rafter run + overhang) × √(1 + (rise ÷ 12)²) -
Cut length
Round up to the next ½ in, so no panel comes up short. Add anything your eave hem or ridge detail needs.
cut length = slope length, rounded up to ½ in -
Panel count
Use the coverage width, not the panel's full width: the seam or the lap takes the rest.
panels = eave length ÷ coverage width, rounded up -
Trim pieces
Each piece covers its length less the lap.
pieces = lineal feet ÷ (piece length − lap), rounded up
Worked exampleA 15 ft run with a 12 in overhang at 6/12: 192 in × 1.1180 = 214.66 in, so each panel is cut at 215 in, 17 ft 11 in. A 40 ft eave with 16 in panels takes 480 ÷ 16 = 30 panels a plane: 60 for both sides of a gable.
| Coverage | Usually | Panels per 100 ft of eave |
|---|---|---|
| 12 in | standing seam | 100 |
| 16 in | standing seam | 75 |
| 18 in | standing seam | 67 |
| 24 in | standing seam | 50 |
| 36 in | R-panel, PBR | 34 |
Panels per 100 ft of eave, rounded up. Check your panel's own coverage width.
Skip the math —upload your plans.
We build your roof in 3D from your plan set, cut every panel to length and measure every trim run: eave, rake, ridge, hip, valley, step and headwall flashing. You spend about 10 minutes checking it against your plans.
Priced per plan setMetal roofing bid, 3D model included
Or see what’s in a metal roofing bid.
Metal roof panel questions.
How many metal roof panels do I need?
Divide the eave length, rake to rake, by the panel's coverage width, and round up. A 40 ft eave with 16 in panels is 480 ÷ 16 = 30 panels. Use the coverage width, not the full width: the seam or the lap takes the rest.
How long should metal roof panels be?
Panel length = (rafter run + eave overhang, both measured level) × pitch factor, rounded up to the next ½ inch. Add anything your eave hem or ridge detail calls for.
What is panel coverage width?
The width one panel covers once it is installed. Standing seam is usually 12, 16 or 18 inches; exposed-fastener panels like R-panel cover 36 inches.
How much metal roof trim do I need?
Measure the eave, rake and ridge in lineal feet. Trim comes in pieces about 10 ft long that overlap a few inches, so divide by the piece length less the lap and round up. Hips, valleys, sidewall and headwall flashing are more pieces on top.
Is this an exact panel order?
No. It's an estimate for one plane at one pitch. Hips, valleys and dormers cut panels to many lengths, which is where hand math goes wrong. Confirm the measurements on site before you order.