Roof Squares Calculator

Three, for standard 3-tab and most architectural lines — each bundle covers about 33.3 sq ft. Heavier designer laminates pack 4 bundles into a square and some luxury lines 5, which is why this calculator makes the bundle count a selector instead of assuming 3. On the default 1,500 sq ft footprint at 6/12 with 15% waste, that's 58 standard bundles.

A pitched roof's surface is its footprint stretched by the slope: multiplier = √(rise² + 12²) ÷ 12. A 6/12 roof is ×1.118, a 12/12 is ×1.414. So a 1,500 sq ft footprint under a 6/12 roof is 1,677 sq ft — 16.8 squares of actual shingle surface. The table above lists every pitch this tool models; the geometry is exact, the estimate around it isn't.

Architectural shingles run $100–$250 per square for materials alone (HomeGuide, 2026) — call it $33–$83 per bundle. Installation labor adds roughly $300–$350 per square, which is why a materials takeoff and a contractor quote are different animals. This calculator prices the materials package only.

It depends on the roll: synthetic underlayment covers 1,000 sq ft per roll, #15 felt 432 sq ft (a 3 ft × 144 ft roll), and #30 felt 216 sq ft. The default job here (~1,929 sq ft to cover) needs 2 synthetic rolls, 5 rolls of #15, or 9 rolls of #30 — buy whole rolls either way. One line this takeoff doesn't price: self-adhering ice-and-water membrane at the eaves and in valleys, which cold-climate codes require and which is cheap insurance everywhere else — figure a couple of extra rolls on top of whichever field underlayment you pick.

Every shingle cut at a valley, hip, rake or dormer throws away part of a bundle; staggering joints eats material too. A long, straight gable roof gets by on 10%. Roofs with hips, open valleys and dormers need 15%, and heavily cut-up roofs can go higher. Suppliers sell whole bundles, so the calculator rounds up after waste.

Measure the ridge plus any hips you'll cap. Cap shingles run about 25 linear ft per bundle (GAF Seal-A-Ridge class) at roughly $2.50–$4.00 per ft; roll ridge vent comes in 20-linear-ft rolls (GAF Cobra class, ≈ $66 list). A simple gable's ridge is the building length — hips on a hip roof add the diagonal runs, so measure them. One nuance: this calculator vents the same length it caps, but only the open ridge gets roll vent — capped hips don't. On a hip roof, either bump the length input to your full capped footage (slightly over-pricing the vent) or run it both ways; the cap line is the one to get right.

No — this is a materials takeoff for DIY planning or checking a supplier delivery. Tear-off, installation labor (HomeGuide: $300–$350 per square), disposal and code items like ice-and-water shield and drip edge are excluded. For the full installed price use the Roof Replacement calculator, which models labor, layers and permits.

Very, if you measure honestly: measure the footprint at the roof's edge — eaves and rakes included, not the walls — and handle complex roofs by adding each rectangle separately (main body, dormers, garage breezeways) before applying the multiplier. Valleys and hips don't change area, only waste. Below a 2/12 pitch asphalt shingles aren't permitted by manufacturers at all — low-slope roofs need membrane systems instead.