Shingle Calculator — Squares & Bundles with Waste
Who this is for: For roofing crews and homeowners pricing a re-roof — how many squares and bundles of architectural shingle the job takes, and what the old roof will weigh in the dumpster.
Enter roof footprint and pitch — get roof area, squares of shingles, 3-bundle bundles with waste, and the weight you'll be hauling to the dump.
Quick answer: Roof area = footprint × pitch multiplier; 3 bundles per square. A 1,600-sf footprint at 6/12 = 1,789 sf ≈ 17.9 squares → 54 bundles + 10% waste ≈ 60 bundles, roughly 2.2 tons on the roof.
L × W of the roof plan
6 for a 6/12 roof
10% simple · 15% cut-up
| Packing | 3 bundles = 1 square (100 sf) |
|---|---|
| Waste default | 10% (15% cut-up roofs) |
| Bundle weight | 60-80 lb (70 used here) |
| Multiplier | Footprint × √(1+(rise/12)²) |
How does the shingle calculator count bundles?
Shingles are sold by the square (100 square feet of finished roof) and packed 3 bundles per square for standard architectural asphalt. The math chain: building footprint × pitch multiplier = roof surface area; area ÷ 100 = squares; squares × 3 = bundles; then a waste factor — 10% for simple gables, up to 15% for hips, valleys, and cut-up plans — because starter course, ridge caps, and cut shingles all come out of the same bundle count. The weight line matters for disposal: a bundle runs 60-80 pounds, so a 20-square tear-off puts roughly 2.1 tons in the dumpster, and most residential bins are rated well below that before overage fees kick in.
Common uses
- Ordering shingles for a re-roof with a defensible waste factor
- Checking a roofer's square count against your own math
- Estimating tear-off weight before renting a dumpster
- Comparing quote areas against the pitch multiplier