Asphalt · Metal · Tile · Cedar Shake

Roofing
Calculator

Enter your roof dimensions and pitch to instantly calculate roof area, squares needed, bundles, and material + labor cost estimate. Free. No signup.

Roof Dimensions

Length (ft)

Width (ft)

Roof Pitch

Pitch multiplier: 1.054 (+5.40% surface area vs. flat)

Roofing Material

Material: $90–$130/sq · Labor: $150–$300/sq

Tear-Off Layers

Layers to remove (0 = new construction or no tear-off)

Waste Factor

Waste: 15%

10% (simple gable)15% (standard)25% (complex)

Enter roof dimensions to see results.

How to Use the Roofing Calculator

Enter Roof Dimensions

Type in the length and width of your roof footprint in feet. This is the horizontal measurement of the roof, not the slope distance. For a gable roof, measure the full rectangular footprint of the house. The calculator applies the pitch multiplier to convert footprint to actual sloped surface area.

Select Roof Pitch

Pitch is the slope of your roof expressed as rise over a 12-inch run. A 4/12 pitch rises 4 inches for every 12 inches of horizontal run — relatively low slope. A 12/12 pitch is steep at 45 degrees. Steeper pitches have more surface area than the base footprint. If you're unsure of your pitch, measure the rise with a level and tape measure from inside the attic.

Choose Your Roofing Material

Select the material you plan to install. Asphalt shingles are the most common and affordable option ($90–$130 per square). Metal roofing is durable and long-lasting ($200–$500/sq). Tile is premium and heavy ($300–$600/sq). Cedar shake offers a natural look ($250–$450/sq). Each material has different labor costs and whether it is sold by the bundle or square.

Add Tear-Off Layers

If you're replacing an existing roof, enter the number of layers to remove. One layer is a standard single-shingle tear-off. Two or three layers means previous reroofs were installed over each other, which adds labor cost. Tear-off runs $50–$100 per square per layer. New construction has zero layers to remove.

Set Waste Factor

The waste factor accounts for cuts, overlaps, and unusable pieces. Standard waste is 10–15% for a simple gable roof. Complex rooflines with multiple valleys, dormers, skylights, and hips need 20–25%. The calculator adds the waste percentage on top of the pitched roof area to give you total material needed.

Roofing Calculator FAQs

How do I calculate roofing squares?

One roofing square equals 100 square feet of roof surface area. To calculate squares: (1) measure the roof footprint length × width in feet; (2) multiply by the pitch factor (e.g., 1.118 for a 6/12 pitch) to get the sloped surface area; (3) add your waste factor (typically 10–15%); (4) divide by 100. For example, a 40 × 25 ft house with a 6/12 pitch and 15% waste = 40 × 25 × 1.118 × 1.15 ÷ 100 = 12.86 squares.

How many bundles of shingles do I need?

Most asphalt shingles come 3 bundles per square (one square = 100 sq ft). Always round up to the nearest whole bundle. If your roof needs 12.86 squares, you need 12.86 × 3 = 38.58 → 39 bundles. Heavy laminate shingles sometimes come 4 bundles per square — check the manufacturer coverage label before purchasing.

What is the pitch multiplier?

The pitch multiplier converts your flat (horizontal) roof footprint into the actual sloped roof area. A flat roof has a multiplier of 1.0. A 4/12 pitch = 1.054 (5.4% more area). A 6/12 pitch = 1.118 (11.8% more). A 12/12 pitch = 1.414 (41.4% more). Steeper roofs require significantly more material and labor. The multiplier is calculated as: √(1 + (rise/12)²).

What does a roofing square cost?

Material costs per roofing square (100 sq ft): asphalt shingles $90–$130, metal roofing $200–$500, clay/concrete tile $300–$600, cedar shake $250–$450. Labor adds another $150–$500 per square depending on material and complexity. A complete roof replacement on a typical 2,000 sq ft home typically costs $8,000–$25,000+ depending on material, pitch, and region.

Should I include labor in the roofing estimate?

Yes. Labor is usually 40–60% of the total roofing project cost. This calculator includes both material and labor ranges so you can see the full project scope. However, actual labor costs vary significantly by region, contractor, and project complexity. Always get 3 quotes from licensed roofing contractors before committing.

What is not included in this roofing calculator?

This calculator covers material quantity, material cost, labor cost, and tear-off cost. It does not include underlayment, ice and water shield, ridge cap, drip edge, flashing, permits, disposal fees, or skylight/chimney work. These add-ons can total $500–$3,000+ depending on your roof. Ask your contractor to itemize these costs in their quote.

How does tear-off affect roofing cost?

Tear-off is removing the existing roofing material before installing new. Most jurisdictions allow up to two layers of shingles on a roof — a third layer requires full tear-off. Tear-off typically costs $50–$100 per square per layer. For a 15-square roof with one layer to remove, that adds $750–$1,500. Full tear-off also allows inspection of the roof deck for rot or damaged sheathing that must be replaced.

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4 Roof Materials

8 Pitch Options

Full Cost Breakdown

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Disclaimer

This roofing calculator is provided for estimating purposes only. Results are based on standard formulas and typical cost ranges. Actual material quantities and costs vary based on roof complexity, local material prices, contractor rates, and regional labor markets. Labor estimates assume a straightforward roof replacement without major repairs or structural work. Tear-off costs assume standard shingle removal — tile and slate tear-off may cost significantly more. Always obtain multiple bids from licensed roofing contractors before making any purchasing or contracting decisions.

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