Estimate roofing materials from the roof's footprint, pitch and a waste allowance. See the true roof area, the material you need to buy and the number of bundles.
Enter the roof length and width (the flat footprint), pick the pitch and set a waste allowance. The pitch inflates the flat area to the true sloped area; the waste allowance covers overlaps, cuts and damage.
No saved calculations yet.
A roofing calculator converts the flat footprint of a roof into its true sloped surface area using the pitch, adds a waste allowance for overlaps and cuts, and converts the result into a number of material bundles.
The pitch multiplier rises with steepness because a steeper slope covers more surface for the same footprint.
It uses a typical ~3 m² per bundle. Coverage varies by product and lap pattern, so check the manufacturer's stated coverage and adjust if needed.
Calculate each section separately and add the material areas together before working out the bundles.