About the Roofing Calculator
Enter the building footprint and roof pitch to estimate the sloped roof area, the number of roofing 'squares' (100 sq ft each), and shingle bundles. Complex roofs need more and waste more.
How it’s calculated
Roof area = footprint × √(1 + (pitch ÷ 12)²) × (1 + waste%). Squares = area ÷ 100; bundles ≈ squares × 3.
Example calculation
A 40 × 30 ft footprint at a 6/12 pitch is about 14.8 squares including waste.
Frequently asked questions
Does this work for complex roofs?
It estimates a simple gable roof. Hips, valleys, dormers, and multiple planes add area and waste — for those, get a professional measurement or use detailed roof plans.
What else do I need besides shingles?
Underlayment, drip edge, starter strip, ridge caps, flashing, and nails — all extra. Steep or tall roofs are best left to professionals.
This is a general material estimate for planning only. Actual quantities vary with waste, offcuts, site conditions, product coverage, and technique. Confirm measurements and coverage rates before ordering, follow local building codes, and round up — running short mid-project is costly.