Roof material orders use squares, not flat floor area.
About this calculator
Roof material orders use squares, not flat floor area. A pitched roof covers more surface than the footprint underneath, and hips, valleys and starter strips eat extra bundles. Guess too low and the crew stops mid-job; too high and you pay for shingles that sit in the shed.
Enter your building footprint in square metres or square feet, pick a pitch (6/12 is common on Indian residential roofs), add a wastage buffer, and optional cost per square. The calculator applies the pitch factor √(1 + (rise/12)²), converts to roofing squares, and estimates material cost.
One roofing square equals 100 square feet (9.29 m²). Complex roofs with dormers or multiple facets need a wastage above 10%. Flat concrete roofs using membrane or tile use different units — this tool targets pitched shingle/metal estimates. Cross-check footprint with the [[square-footage]] calculator, compare bulk material volume with [[volume]], and use [[concrete]] when sizing a flat roof slab separately from the finish layer.
Common uses
- Estimating shingle bundles before re-roofing a house
- Converting m² footprint to roofing squares for supplier quotes
- Comparing material cost at different pitch and wastage assumptions
- Quick sanity check on a roofer
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Frequently asked questions
What is a roofing square?
One square covers 100 square feet of roof surface. Three-tab shingle bundles often cover about one square per three bundles, but always read the manufacturer
How does pitch change the area?
A 6/12 pitch multiplies footprint area by about 1.12. A 12/12 (45°) pitch multiplies by √2 ≈ 1.41. Flat roofs use a factor of 1.
Should I add extra for hips and valleys?
Yes. Simple gable roofs may need only 10% wastage. Cross-gables, dormers and many valleys often need 12–15%. Measure each facet separately on complex layouts.
Can I enter footprint in square feet?
Switch the unit dropdown to sq ft. The calculator converts internally and reports squares in the standard 100 sq ft unit.
Does this include labour?
No. Cost per square here is material only. Labour varies by pitch, storeys, tear-off and local rates. Get itemised quotes for installation.