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EspañolRoofing calculator (squares and shingle bundles)
Enter the house length and width including the overhang, and the roof pitch (rise in inches per 12 in of run).
How many squares is my roof?
Everything happens on your device: nothing is uploaded to the internet.
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Roofing calculator (squares and shingle bundles): what it is for
Enter the length and width of the house plus the overhang and the roof pitch, or type the area if you already know it. The calculator applies the pitch factor to get the real roof surface, converts it to squares, adds the waste you choose and estimates the bundles of shingles, the rolls of underlayment and the cost per square.
Use about 10% waste for a simple gable roof and 15% or more for hip roofs and roofs with valleys and dormers. Ridge caps and starter strips are extra; ask your supplier.
How to use
- Enter the footprint and the pitch.
- Choose the waste and bundles per square.
- Read the squares, bundles and cost.
When to use it
- Reroofing estimates.
- Checking a roofer's quote.
- Shed and garage roofs.
Frequently asked questions
What is a roofing square?
A square is 100 square feet of roof surface. Roofers price jobs per square, and a roof of 2,400 sq ft is 24 squares.
How many bundles of shingles are in a square?
Most architectural and 3-tab asphalt shingles come 3 bundles per square, so each bundle covers about 33.3 sq ft. Some heavier designer shingles take 4 or 5 bundles per square; check the wrapper.
How does the pitch change the roof area?
A sloped roof has more surface than the flat footprint under it. Multiply the footprint by the pitch factor: about 1.054 for a 4/12 pitch, 1.118 for 6/12, 1.202 for 8/12 and 1.414 for 12/12. The calculator uses the exact factor √(rise² + 12²) ÷ 12.
Is it really free?
Yes, 100% free. No sign-up, no subscription and no usage limits. All Tools123 tools are free and run right in your browser.