Last checked
March 28, 2026
We checked the calculator logic, page links, and support content used on this page.
Roofing Estimating
Nominal coverage and effective coverage are not the same thing
The label on the pack is only useful once laps, overlaps, and real roof geometry are accounted for.
How to use it
Use it as a planning estimate
Use this guide to build a rough material estimate, then confirm the final order against product data and site conditions.
Why trust it
See how the site is maintained
Read the calculator methodology and editorial policy for the standards behind these pages.
Use the calculator first
The quickest path is to start with Shed Felt Calculator, then use this guide to sense-check the result and decide what to buy next.
Why this page exists
Best for sheds, garages, simple roofs, and early roofing material checks where the buyer needs a fast but practical order estimate.
Core assumption
Roofing estimates rely on covered area, lap or overlap allowances, and the fact that roof shape and pitch often increase the real material take-off above a simple plan area.
Common mistake
Common issues include ignoring overlap, failing to allow for cuts at edges and ridges, and treating every roof as if it behaves like a simple rectangle.
Next step links
Open the full Roofing Estimating tool set or go straight to the Shed Felt Calculator.