Metal Roof Calculator
A metal roof calculator finds how many metal panels you need by dividing the roof's true area by the coverage of one panel (panel width times length), then adding waste for overlap and cuts. Enter your roof dimensions, pitch and panel size below to get the panel count.
Enter footprint dimensions to see the materials.
Estimate only. Confirm against your local building code: stairs, framing, rebar, roofing and retaining walls are structural and code-dependent. This site does not provide engineering judgment.
How Many Metal Roofing Panels Do You Need?
To find metal panels, calculate the true roof area (footprint adjusted for pitch), then divide by the coverage of one panel. Panels are sized by their effective width (after side overlap) times their length. A 1,500 square foot roof with panels covering 3 square feet effective each needs about 500 linear feet of panel, organized into rows. The calculator works from your panel width and roof size, plus waste for end laps.
Why Is Metal Roof Estimating Different?
Metal roofing is estimated by panels and linear feet rather than bundles, because panels run in continuous lengths up the slope with side laps between them. The effective coverage width is less than the panel's actual width due to the overlap. This is why you use the panel's coverage width, not its total width, which the calculator accounts for so you order enough panels.
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Frequently asked questions
- How many metal roof panels do I need?
- Divide the true roof area by each panel's effective coverage (width after overlap times length), then add waste for end laps. The calculator does this from your panel size.
- How is metal roofing measured?
- By panels and linear feet running up the slope, using the panel's effective coverage width after side overlap, not its full width.