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Roofing Squares
—squares
Entrez les dimensions ci-dessus
Shingle Bundles
—bundles
Basé sur la densité de Roofing (0 t/vg³)
Calculatrice Gratuite de Roofing
Roofing Calculator: Squares, Bundles and True Cost
Enter your roof dimensions into the roofing calculator above and get squares, shingle bundles, underlayment rolls, and 2026 cost estimates for your project.
Common Roof Sizes: Quick Bundle Count
| 1,500 sq ft roof (15 squares) | 50 bundles + 4 felt rolls |
| 2,000 sq ft roof (20 squares) | 66 bundles + 5 felt rolls |
| 2,500 sq ft roof (25 squares) | 83 bundles + 7 felt rolls |
| 3,000 sq ft roof (30 squares) | 99 bundles + 8 felt rolls |
Roofing Guide de Référence
Roofing Costs in 2026 (per Square = 100 sq ft)
| 3-tab shingles (materials) | $120 - $180 |
| Architectural shingles (materials) | $150 - $250 |
| Underlayment roll (felt, 4 sq) | $25 - $40 |
| Ice & water shield roll | $70 - $95 |
| Professional install (per square) | $450 - $700 |
Prices are 2026 US averages. Actual costs vary by region and supplier.
Profondeurs recommandées pour Roofing
| Projet / Utilisation | Profondeur recommandée |
|---|---|
| Low slope (3/12 to 4/12) | Pitch factor 1.0 - 1.05 |
| Medium slope (5/12 to 7/12) | Pitch factor 1.10 - 1.20 |
| Steep slope (8/12 to 12/12) | Pitch factor 1.25 - 1.40 |
| One roofing square | 100 sq ft of roof area |
Comment calculer le volume de Roofing
La plupart des fournisseurs vendent le roofing à la verge cube. Pour convertir la surface en verges cubes, utilisez cette formule :
Notre calculatrice multiplie également le résultat par 0 tonnes/vg³ (densité standard) pour estimer le poids.
Roofing Calculator: Squares, Pitch Factors, and Waste Explained
A roofing calculator converts your roof footprint into squares, then into shingle bundles. The core formula is: (Length x Width x Pitch Factor) / 100 = Squares. Squares x 3 = Bundles (for standard 3-tab shingles). A 40x50 foot roof with a 6/12 pitch: 2,000 x 1.15 = 2,300 sq ft = 23 squares = 69 bundles, plus 10% waste = 76 bundles.
Pitch factors correct for the fact that a sloped roof has more surface area than its flat footprint. The factor is the hypotenuse of the pitch triangle: for a 6/12 pitch, it is the square root of (1 + (6/12)^2), which equals 1.118. Our roofing calculator uses standard pitch brackets rather than making you do trigonometry: low slope multiplies by 1.0 to 1.05, medium by 1.10 to 1.20, steep by 1.25 to 1.40.
Waste factors for roofing depend on roof complexity, not just area. A simple gable roof (two rectangular planes) wastes about 10%: mostly ridge cuts and starter strips. Hip roofs waste more (12-15%) because every hip requires angled cuts. Roofs with dormers, valleys, chimneys, and skylights push to 15% or beyond. Each penetration means flashing, and each valley means woven or cut shingles that consume extra material.
Underlayment math is separate from shingle math. Standard #15 asphalt felt comes in rolls covering 4 squares (400 sq ft) with the required overlap. Synthetic underlayment is lighter, stronger, and covers 10 squares per roll, making it the better value despite higher per-roll cost. Ice and water shield, required by code at eaves in cold climates, is measured in linear feet along the eave: buy enough to extend 24 inches past the interior wall line.
Shingle bundle counts are not universal. The industry standard of 3 bundles per square applies to 3-tab and most architectural shingles, but heavy designer shingles sometimes pack 4 or 5 bundles per square. Always check the wrapper: it states both the bundle count per square and the coverage. When our calculator outputs bundle counts, it assumes the standard 3-per-square packaging and notes where to verify.
Conseils de pros
1
Never order exactly the calculated bundle count. Shingle color varies by manufacturing lot, and a mid-project reorder can produce a visible shade difference across your roof slope. The 10-15% waste factor in our calculator covers this.
2
Count your roof planes before ordering. Each valley, dormer, and chimney adds cutting waste. A simple gable roof needs 10% extra; a complex roof with multiple dormers needs 15% or more.
3
Ice and water shield is not optional in cold climates. Code requires it along eaves in regions with freeze-thaw cycles. It costs about $80 per roll but prevents the most expensive roof failure: ice dam leaks.
4
A roofing square is 100 square feet, and standard 3-tab shingles come 3 bundles per square. Architectural shingles are heavier and sometimes pack 4 bundles per square: check the wrapper, because bundle counts vary by manufacturer.
Foire aux questions
How many shingle bundles do I need for my roof?▼
Calculate roofing squares (roof area / 100), multiply by 3 bundles per square for standard shingles, then add 10-15% waste. A 2,000 sq ft roof is 20 squares, needing 60 bundles plus waste (66-69 total). Our roofing calculator above handles pitch adjustment and waste automatically.
What is a roofing square?▼
A roofing square is 100 square feet of roof area. Roofers use squares because shingle packaging is standardized around it: one square of standard 3-tab shingles equals exactly 3 bundles. A 2,400 sq ft roof is 24 squares. The term has nothing to do with the shape of your roof.
How do you account for roof pitch in calculations?▼
Multiply your flat footprint area by a pitch factor: 1.0 to 1.05 for low slopes (3/12-4/12), 1.10 to 1.20 for medium slopes (5/12-7/12), and 1.25 to 1.40 for steep roofs (8/12-12/12). A 2,000 sq ft footprint with a 6/12 pitch is actually 2,200 sq ft of roof surface. Our calculator applies the pitch factor automatically.
How much does a new shingle roof cost in 2026?▼
Asphalt shingle roofing costs $450 to $700 per square installed in 2026, or $4.50 to $7.00 per sq ft. A typical 2,000 sq ft roof (20 squares) runs $9,000 to $14,000 professionally installed. Materials alone are $150 to $250 per square. Architectural shingles add 20-30% over 3-tab.
How much underlayment do I need?▼
One roll of standard #15 felt underlayment covers 4 squares (400 sq ft). Synthetic underlayment rolls cover 10 squares (1,000 sq ft) per roll. For a 20-square roof, you need 5 rolls of felt or 2 rolls of synthetic. Ice and water shield is sold separately for eaves and valleys.