Work out how many bundles of shingles you need with our free roof shingle calculator. Get underlayment, drip edge, ridge cap, nails, and total cost.
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Shingle takeoffs are fussy. Miss the pitch multiplier and you order short. Forget the waste factor and you’re back at the supply house mid-job. This roof shingle calculator handles the geometry and the materials in one pass. Pick your roof type, enter building length, width, and pitch. The tool returns roof surface area, squares, bundle count, underlayment rolls, drip edge, hip and ridge cap, starter strip, nails, sealant, and a full cost estimate. Seven shingle presets load the right coverage per bundle, from 3-tab to luxury and synthetic. Contractors use it for bids. Homeowners use it to check a quote before signing. Imperial and metric both work, and everything runs in your browser.
Choose your currency and unit system. Sixteen currencies and both imperial and metric are supported.
Pick a roof type. Gable, hip, shed, gambrel, mansard, or direct area entry.
Enter building length and width. For direct area mode, skip to total roof surface area.
Set the roof pitch. Use rise:12, degrees, or percent.
Add the overhang. Twelve inches is typical.
Choose a shingle preset. 3-tab, architectural, premium, luxury, metal, synthetic, or wood shake.
Set waste factor and coverage per bundle. Presets fill these automatically.
Toggle drip edge, hip and ridge cap, valley flashing, and starter strip. Set underlayment type and fasteners.
Enter unit costs and read the summary. The result panel shows bundles, squares, and total cost.
Roof area drives everything. The tool converts your building footprint to plan area, adds overhangs, then multiplies by the pitch factor.
Formula: Roof Surface Area = Plan Length × Plan Width × √(1 + Pitch²)
Formula: Squares = Roof Surface Area ÷ 100 ft² (or 9.29 m²)
Formula: Area with Waste = Roof Area × (1 + Waste % ÷ 100)
Formula: Bundles Required = Ceiling(Area with Waste ÷ Coverage per Bundle)
Formula: Total Nails = Squares Required × Nails per Square
Plan length is building length plus two overhangs. Plan width is building width plus two overhangs. Pitch is the rise over 12 expressed as a decimal.
For a gable roof, ridge length equals plan length and eave length is twice plan length. Hip roofs shorten the ridge by the building width and add four hip ridges. Shed roofs have one eave and no ridge. Gambrel and mansard use multipliers that reflect their two-slope geometry.
Bundle count comes from area with waste divided by coverage per bundle. Architectural shingles cover about 33.3 ft² per bundle. Luxury shingles cover less, often around 25 ft². The preset dropdown handles these differences.
Underlayment rolls divide roof area by coverage per roll. Drip edge runs along eaves and rakes. Starter strip runs along eaves only. Hip and ridge cap covers the full ridge plus any hips.
A 40-foot by 30-foot gable roof at 6:12 pitch with 12-inch overhangs. Architectural shingles at 33.3 ft² per bundle. 10% waste. Synthetic underlayment, 1,000 ft² per roll. 320 nails per square.
Step 1 — Plan dimensions. Length = 40 + 2 = 42 ft. Width = 30 + 2 = 32 ft.
Step 2 — Pitch ratio. 6/12 = 0.5. Multiplier = √(1 + 0.25) = √1.25 = 1.1180.
Step 3 — Roof area. 42 × 32 × 1.1180 = 1,502.6 ft².
Step 4 — Squares. 1,502.6 ÷ 100 = 15.03 squares.
Step 5 — Area with waste. 1,502.6 × 1.10 = 1,652.9 ft².
Step 6 — Bundles. 1,652.9 ÷ 33.3 = 49.6, rounded up to 50 bundles.
Step 7 — Ridge length. 42 ft. Eave length = 2 × 42 = 84 ft. Rake length = 4 × slope of half-width. Half-width = 16 ft. Slope = √(16² + 8²) = √320 = 17.89 ft. Rake = 4 × 17.89 = 71.6 ft.
Step 8 — Drip edge. 84 + 71.6 = 155.6 ft. Starter strip = 84 ft.
Step 9 — Underlayment. 1,502.6 ÷ 1,000 = 1.5, rounded to 2 rolls.
Step 10 — Nails. 15.03 squares × 320 = 4,810 nails. Boxes = ceil(4,810 ÷ 5,000) = 1 box.
Step 11 — Cost at $34 per bundle, $120 per underlayment roll, $2.50/ft drip edge, $6/ft ridge, $4/ft starter, $45 per box of nails, $9 per sealant tube (4 tubes), $1.75/ft² labor. Shingles = 50 × 34 = $1,700. Underlayment = 2 × 120 = $240. Drip edge = 155.6 × 2.50 = $389. Ridge = 42 × 6 = $252. Starter = 84 × 4 = $336. Nails = $45. Sealant = $36. Material subtotal = $2,998. Labor = 1,502.6 × 1.75 = $2,629.55. Total = $5,627.55.
Interpretation: Order 50 bundles of architectural shingles. You need 2 rolls of underlayment, 156 feet of drip edge, 42 feet of ridge cap, 84 feet of starter strip, and 1 box of nails. Material runs about $3,000 before labor. At $5,628 total, cost per square is $374, which sits in the typical range for architectural asphalt installed.
Divide area with waste by 33.3 ft² per bundle and round up. A 15-square roof with 10% waste needs about 50 bundles. Three bundles cover one square for asphalt shingles.
Multiply plan length by plan width, then multiply by the pitch multiplier. Add overhangs to length and width first. A 30×40 building with 12-inch overhangs and a 6:12 pitch has a roof area of about 1,503 ft².
100 square feet of roof surface. Shingles are sold in bundles of three per square. A 20-square roof needs 60 bundles before waste.
Asphalt shingles installed: $350 to $550 per square. Architectural: $450 to $700. Luxury or designer: $600 to $900. A 15-square roof with architectural shingles typically lands between $6,750 and $10,500.
10% for a simple gable roof. 15% for a hip roof or one with valleys. 20% for complex roofs with dormers and multiple pitch changes.
Yes. Underlayment is required by code in most jurisdictions and provides a secondary water barrier. Synthetic underlayment is standard. Peel-and-stick is used at eaves and valleys in cold climates.
An L-shaped metal strip along eaves and rakes. It keeps water from wicking back under shingles and protects the fascia. Most codes require it. The calculator includes drip edge length for both eaves and rakes.
320 nails per square for hand-nailing. High-wind areas require six nails per shingle instead of four, which pushes the count to about 480 per square.
A ridge cap with a vent channel that lets hot air escape from the attic. Vented ridge is code-required in many jurisdictions. It installs the same way as a standard ridge cap.
Measure 12 inches horizontally along the roof, then measure the vertical rise. The ratio of rise to 12 is your pitch. Six inches of rise over 12 inches of run is 6:12.
Sometimes. Building codes usually allow a second layer if the existing roof is in good shape and the structure can handle the weight. Strip the old roof if it has two or more layers already, or if it’s curling or damaged.
Asphalt: 15 to 30 years. Architectural asphalt: 25 to 40. Luxury: 30 to 50. Metal shingles: 40 to 70. Wood shake: 25 to 40. Climate, ventilation, and installation quality all affect lifespan.
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