Settings
Input Areas
Enter dimensions for each roof area. Width is measured perpendicular to the sheet corrugations. Slope length runs along the corrugations. Side-lap is in corrugation counts. End-lap is linear overlap between stacked sheets.
| # | Area name | Roof width (mm) | Slope length (mm) | Sheet total width (mm) | Corrugation pitch (mm) | Side-lap (corrugations) | Effective cover width (mm) | Sheet length (mm) | End-lap length (mm) | Gable overhang each side (mm) | Eave overhang (mm) | Waste % | Notes | Remove |
|---|
Results
| Area | Sheets across | Rows along slope | Total before waste | Waste % | Total with waste | Effective cover width (mm) | Effective length per sheet (mm) | Notes |
|---|---|---|---|---|---|---|---|---|
| Grand total | 0 | 0 | ||||||
Totals include your selected waste percentage using ceiling rounding where appropriate.
Formula used
Effective cover width (ECW) = Sheet total width − (Corrugation pitch × Side‑lap corrugations)
Width to cover = Roof width + 2 × Gable overhang
Sheets across = ceil( Width to cover ÷ ECW )
Effective length per sheet = Sheet length − End‑lap length
Rows along slope = ceil( (Slope length + Eave overhang) ÷ Effective length per sheet )
Total sheets (before waste) = Sheets across × Rows along slope
Total with waste = ceil( Total before waste × (1 + Waste%/100) )
Notes: ECW is often published by manufacturers; if known, toggle “effective cover width” and enter directly. Always verify profile-specific ECW and lap requirements.
How to use this calculator
- Select units. You may switch between millimeters and inches at any time.
- For each roof area, enter width, slope length, sheet dimensions, laps, and overhangs.
- If you know profile ECW from a datasheet, enable the ECW toggle and enter it.
- Click Calculate to populate the results table and totals.
- Use Download CSV or Download PDF to export a summary.
- Use Copy Shareable URL to embed inputs in a link for teammates.
- Repeat for additional areas; use waste% to include cutting and damage allowances.
Example data
These example rows reflect a small porch roof and a larger shed roof using common corrugated profiles.
| Area name | Roof width (mm) | Slope length (mm) | Sheet total width (mm) | Pitch (mm) | Side-lap (corr) | ECW (if known) | Sheet length (mm) | End-lap (mm) | Gable overhang (mm) | Eave overhang (mm) | Waste % | Notes |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Porch | 2400 | 2800 | 840 | 76 | 1 | - | 3000 | 150 | 50 | 50 | 7 | Color-coated |
| Shed | 5200 | 4200 | 762 | 76 | 1.5 | - | 3600 | 150 | 50 | 60 | 8 | Zincalume |
FAQs
It is the usable sheet width after side-lap deduction. Manufacturers often publish ECW for each profile and side-lap. Enter it directly if known.
Typical laps are 1 to 2 corrugations depending on exposure and wind. Follow local codes and product datasheets for your site and profile.
Yes. Where sheets are stacked vertically, the overlap reduces effective coverage. If you can order full slope-length sheets, rows may reduce to one.
Yes. Add a percentage for cutting, damage, and spares. Complex roofs, fragile finishes, and DIY installs often need a higher allowance.
Gable overhangs increase width to cover; eave overhangs increase slope length to cover. Both can increase sheets across and rows along the slope.
Yes. Use “Add Area” for each rectangle. The results show per‑area counts and grand totals. For odd shapes, split into rectangles.
This calculator uses industry‑standard arithmetic. Final counts can differ due to profile specifics, fixing patterns, and ridge/valley details. Confirm with suppliers.
Disclaimer: This tool provides planning estimates only. Always confirm profile cover widths, lap requirements, and fastener patterns with manufacturer literature and local building codes.