Metal Roofing Material Calculator

Panels = the plane’s width in inches ÷ the usable width of one panel, rounded up: a plane 40 ft wide takes 14 panels of 36 in, each 16 ft long, or 16 with 10% extra.

Your measurements

Example

Use the unit shown for each box, or type another one: 12 ft 6 in, 150 in, 3.8 m and 600 mm all work, as do the marks on a tape measure.

Roof plane 1

Slope length (ft) Eave length (ft)

Panel width before side lap Side lap If your supplier gives installed coverage width, use that width and leave the side lap at zero.

Details Package sizes, prices and materials

Extra for cuts (%) Eave trim length Usable eave trim per piece Rake trim length Usable rake trim per piece Ridge caps length Usable ridge caps per piece Hip caps length Usable hip caps per piece Valley trim length Usable valley trim per piece Pipe boots from your plan Vent flashings from your plan Chimney flashing kits from your plan Fasteners per panel Your price per panel ($)

Example: replace these measurements

Your material list

16 full-length panels

640 sq ft measured

Your measured layout

Shown area and direction, schematic. The lines are not a cutting, fastening or installation plan.

Your shopping list

16 full-length panels

Quantities and package details

Panels before extra: 14
Usable panel width: 36 in
Roof plane area: 640 sq ft
Panel lengths: 16 ft
Eave trim pieces: Enter measured length and usable coverage
Rake trim pieces: Enter measured length and usable coverage
Ridge-cap pieces: Enter measured length and usable coverage
Hip-cap pieces: Enter measured length and usable coverage
Valley trim pieces: Enter measured length and usable coverage
Pipe boots: Enter count from your plan
Vent flashings: Enter count from your plan
Chimney flashing kits: Enter count from your plan
Fasteners before spares: Enter fastening schedule

The calculation

36 − 0 = 36 in usable panel width
Plane 1: ceil(40 × 12 ÷ 36) = 14 panels, each 16 ft long.

Common questions

How do I work out how many metal roof panels I need?

Divide the eave length of each roof plane by the width each panel covers after the side lap, and round up. Each panel runs the full slope from eave to ridge, so order them cut to that length.

What is the difference between panel width and coverage width?

Panels overlap at the side lap, so each one covers less than its full width. Enter the full width and the lap, or enter the coverage width your supplier gives and leave the lap at zero.

Which trim does a metal roof need?

Each edge has its own trim: eaves, rakes, ridges, hips and valleys. Measure each, divide by the usable length of one piece after overlaps, and round up. The list keeps them on separate lines so none is left off the order.

How to plan the quantity

Measure each roof plane from ridge to eave along the slope. Measure the eave across the bottom. This is different from the horizontal footprint used for shingles.

Panel width minus side lap gives the width that covers the roof. If you already have installed coverage width, enter it with no additional lap deduction. This tool uses full-length panels; end-lapped panels need a supplier schedule.

Enter measured eaves, rakes, ridges, hips and valleys separately, with the usable coverage of each trim piece after overlaps. Keep pipe boots, vent flashings and chimney kits separate using the counts on your roof plan.

Before you order

Panel profile, slope suitability, laps, clips, screw pattern and penetrations are product-specific. Enter their requirements from the selected system.
This counts rectangular planes without nesting offcuts. Hip and valley cuts need a panel schedule from the roof plan.

Before ordering, read the guide: How many bundles of shingles do I need? Squares, waste and accessories. Or choose another calculator.