A clear result in a few inputs.
- Enter the requested values.Use consistent units and the real values for your scenario.
- Read the main result and breakdown.NumLuma recalculates immediately when an input changes.
- Check the formula and assumptions.Use the supporting context before making a real-world decision.
What this calculator does
Roofing materials in the US are commonly discussed in squares, where one roofing square equals 100 square feet of roof surface. This calculator converts a known roof surface area into squares after applying your waste allowance.
What to know before you use the result
- Enter actual roof surface area, not building footprint, unless pitch has already been accounted for.
- One roofing square equals 100 ft².
- Valleys, hips, dormers and complex layouts can increase waste.
Common mistakes to avoid
- Using horizontal footprint area for a sloped roof.
- Treating the calculator as a structural or code check.
- Assuming all roofing products package one square in the same number of bundles.