RoofMetric
How the math works
A "square" in roofing is 100 square feet of roof surface. So 2,000 sq ft of roof = 20 squares.
But if you measured from the floor plan (footprint), you need to multiply by the pitch factor to get the actual sloped surface:
- 4/12 pitch → multiply by 1.054
- 6/12 pitch → multiply by 1.118
- 8/12 pitch → multiply by 1.202
- 10/12 pitch → multiply by 1.302
- 12/12 pitch → multiply by 1.414
Then add waste (10–18%) for cuts and overhangs. The result is how much material you need to order, not how much covers the roof.
How many bundles of shingles?
Three bundles per square is the standard. So 23 squares = 69 bundles. Order 70 for cushion.
Architectural shingles average $35–$45 per bundle at supplier prices, so material cost: roughly $2,450–$3,150 for shingles alone. Add underlayment, ice & water shield, drip edge, ridge cap, and flashings.
Want the full quote — not just shingles?
This calculator gives you the squares number. To turn that into a complete bid (tear-off, labor, materials, markup, signed PDF), you need a proper estimating tool. Read our full guide or skip ahead and let RoofMetric do every step in 5 minutes.