Roof covering units.
Measure each actual roof plane on its sloping surface.
Read the right quantitative data
Effective coverage per selected unit or pack.
Check this ordering assumption
A horizontal footprint is smaller than the surface of a sloped plane.
Covering choice, pitch suitability and fixing pattern are not selected here.
A worked quantity method
This illustrative set of supplied inputs demonstrates Roof Covering Units Calculator. Replace the example measurements and product figures with your own before ordering.
| Supplied input | Metric display | US display |
|---|---|---|
| Effective installed unit width | 1,000 mm | 39.37 in |
| Effective installed unit length | 2 m | 6.56 ft |
| Specified cap run length | 6 m | 19.69 ft |
| Effective cap length per unit | 1.5 m | 4.92 ft |
| Waste allowance | 10 % | 10 % |
| Roof plane 1: Slope length | 5 m | 16.4 ft |
| Roof plane 1: Plane width | 6 m | 19.69 ft |
Roof covering units to purchase: 20 units
- Cover units before allowance
- 18
- Cap units to purchase separately
- 5
Fastener design, underlay requirements, wind resistance and roof suitability are not determined here.
Open this example in the full calculatorYour measurement and product-data sheet
Record what you know and mark verified items ready. Notes save on this browser after you edit them. Download a copy before clearing browser data.
Measure each actual roof plane on its sloping surface.
Effective coverage per selected unit or pack.
A horizontal footprint is smaller than the surface of a sloped plane.
Input for Roof Covering Units Calculator. Record the value with its unit and quantity basis.
Input for Roof Covering Units Calculator. Record the value with its unit and quantity basis.
Input for Roof Covering Units Calculator. Record the value with its unit and quantity basis.
Input for Roof Covering Units Calculator. Record the value with its unit and quantity basis.
Input for Roof Covering Units Calculator. Record the value with its unit and quantity basis.
Input for Roof Covering Units Calculator. Record the value with its unit and quantity basis.
Input for Roof Covering Units Calculator. Record the value with its unit and quantity basis.
Choose your next calculation
Roof Covering Units Calculator
Count effective roof-covering rectangles per plane and separately specified ridge-cap units.
Roof Plane Area Calculator
Sum the geometric area of specified roof planes from horizontal run, rise and ridge length.
Turn the estimate into an order
- Confirm that all quantities use the same measured basis and the selected product's current data.
- Keep different products, finishes and handed variants in separate purchase lines.
- Review exact demand and whole-pack purchase quantities before entering your quoted prices.
- Record compatible stock already on hand, then save the remaining order in your browser project.
Measurement and purchase guides
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Reviewed 6 October 2026. Geometry and purchase arithmetic use your measurements and selected specifications. Calculation scope.