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Metal Roof Panel Calculator

Count standing-seam or corrugated panels for a roof slope, allowing for side laps and the ridge overlap.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-26 · v1.0.0

Market
Imperial · sales tax
39.37 ft1.5 ft
Schematic, drawn to the proportions you entered — not to scale on screen.

Panels required

27 panels per slope

High confidence

Counts full-length panels on a rectangular slope. Ridge caps, eave and gable trims, closures and fixings are separate items.

Panel length required
16.4 ft
Total linear panel
442.91 ft
Slope area
645.83 ft²
Both slopes
54 panels
Coverage of the last panel used
0.39 ft

At the values currently entered, the panels required works out to 27 panels per slope. Note that eave length sits at the low end of the range this calculator was checked against, so treat the output as indicative rather than settled. Figures are shown for United States, where IRC 2024 is the governing residential reference; switch the market above if you are building elsewhere.

Add the equipment this sizes

This result is a specification — 27 panels per slope — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • Panel coverage width is the net width after the side lap, and is what manufacturers publish for ordering
  • MCA (Metal Construction Association) installation guidance: panels are run full length from eave to ridge wherever possible to avoid an end lap

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Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.

Still deciding? Metal Roof vs Shingles — the factors that actually differ, with no invented prices.

Frequently asked questions

Coverage width or panel width?
Always coverage. The overall width includes the part that disappears under the next panel's side lap. A 470 mm panel covering 457 mm is 3% narrower in use, and ordering against the overall width leaves the last run short on a wide roof.
Should panels run the full length of the slope?
Wherever the manufacturer's maximum length allows. An end lap is a detail that has to be sealed and fixed correctly, and it is the most common place a metal roof leaks. Long single panels also expand and contract as one piece, which is why the fixing method matters more as they get longer.
Does this include the ridge and trims?
No — panels only. Ridge caps, eave trim, gable or barge trim, valley flashing, closures and the correct fixings are separate and together are a substantial share of a metal roof's material cost.