About Roof Square Calc

Roof Square Calc is a free planning tool for people estimating roof area and material quantities. It converts horizontal measurements and pitch into sloped area, roofing squares and package counts.

What the tool does

It uses transparent geometry: each non-overlapping rectangular footprint is multiplied by its pitch factor. You can adjust waste and package coverage. Worked examples and assumptions appear beside the results and below each calculator.

What an estimate leaves out

We do not inspect your roof or determine structural safety, building-code compliance, roof-system compatibility or installation details. We do not supply a professional quantity survey. Dormers, intersecting gables, openings, starter courses, flashing and ridge caps need separate attention.

Check before you order

Measure carefully, use the actual product’s usable coverage, and ask a qualified roofer to verify roof geometry and material requirements. Estimates only; do not use these results as a construction specification, commercial quote or tax basis.

Your measurements stay with you

Calculations run on your device. This version has no accounts, advertising, analytics or saved measurement history. Read the privacy policy.

Formula sources and further reading

The slope factor follows the Pythagorean theorem. Angle conversions use the inverse tangent of rise divided by run. For general mathematical background, see the Pythagorean theorem explanation. For a product order, consult the selected manufacturer’s own installation instructions.