Roofing Calculator
Roof Area, Shingles & Cost Estimator
Calculate your roof square footage, estimate shingle bundles and roofing materials, and compare costs for asphalt, metal, tile, and slate — all in one free roof area calculator.
Step 1: Roof Dimensions
Building footprint: 1,200 sqft
How the Roofing Calculator Works
Three simple steps to estimate your roof replacement or new installation costs.
Enter Roof Dimensions
Input your building length and width in feet, choose from five roof types (gable, hip, gambrel, flat, or shed), and set the roof pitch. The roof sq ft calculator instantly computes your total roof area.
Choose Your Material
Select from six roofing materials including asphalt shingles, metal standing seam, corrugated metal, clay tile, and natural slate. The roofing material calculator adjusts your estimate accordingly.
Get Your Estimate
View roofing squares, shingle bundles, underlayment rolls, drip edge, and a side-by-side cost comparison for all six materials. Use the results as a roof estimate calculator for budgeting.
Roofing Material Cost Comparison (2026)
Average installed cost per roofing square (100 sqft) for the six most popular materials. Use this roofing square calculator reference alongside your estimate.
| Material | Low ($/sq) | High ($/sq) | Lifespan |
|---|---|---|---|
| Asphalt 3-Tab Shingles | $350 | $550 | 15-20 yrs |
| Architectural Shingles | $400 | $700 | 25-30 yrs |
| Metal Standing Seam | $700 | $1,400 | 40-70 yrs |
| Metal Corrugated | $350 | $650 | 25-40 yrs |
| Clay / Concrete Tile | $800 | $1,800 | 50-100 yrs |
| Natural Slate | $1,500 | $3,000 | 75-150 yrs |
Costs include materials and professional installation. A steel roof calculator or metal roof price calculator estimate will depend on panel profile and gauge. Actual costs vary by region and contractor.
Roof Type Guide: Gable vs Hip vs Gambrel vs Flat
Each roof style affects material needs, cost, and structural complexity. Here is when to use each type in your roof area calculator estimate.
Gable Roof
1.0x base areaThe most common roof style with two sloping sides meeting at a ridge. Simple to build, excellent ventilation, and cost-effective. Works with all materials. Ideal for most residential homes in moderate climates.
Hip Roof
1.05x base areaAll four sides slope downward to the walls. More stable in high winds and hurricanes than gable roofs. Requires approximately 5% more material due to hip ridge cuts and triangular sections.
Gambrel Roof
1.15x base areaA barn-style roof with two different slopes on each side — the lower slope is steeper. Provides maximum attic or upper-floor space. Common on Dutch Colonial and "barn house" designs. Uses about 15% more material.
Flat Roof
1.0x (footprint area)Not truly flat — has a slight slope (usually 0.25-0.5 inches per foot) for drainage. Popular for commercial buildings and modern residential architecture. Requires specialized membrane materials like TPO, EPDM, or built-up roofing.
Shed Roof
Pitch multiplier onlyA single sloping surface, essentially half of a gable roof. Common for additions, porches, and modern single-story homes. The simplest and most affordable roof to construct, with easy drainage in one direction.
Roof Pitch Reference Table
Pitch is expressed as rise over a 12-inch run. Use this table alongside the roof square footage calculator to understand how slope affects material needs.
| Pitch | Degrees | Multiplier |
|---|---|---|
| 0/12 | 0° | 1.000 |
| 1/12 | 4.8° | 1.003 |
| 2/12 | 9.5° | 1.014 |
| 3/12 | 14.0° | 1.031 |
| 4/12 | 18.4° | 1.054 |
| 5/12 | 22.6° | 1.083 |
| 6/12 | 26.6° | 1.118 |
| 7/12 | 30.3° | 1.158 |
| 8/12 | 33.7° | 1.202 |
| 9/12 | 36.9° | 1.250 |
| 10/12 | 39.8° | 1.302 |
| 11/12 | 42.5° | 1.357 |
| 12/12 | 45.0° | 1.414 |
Multiply your building footprint by the pitch multiplier to get the actual roof surface area. Pitches above 6/12 typically require additional safety equipment and may increase labor costs.
Frequently Asked Questions
Common questions about our free roofing calculator, roof estimate calculations, and roof replacement costs answered.
Replacing your siding too?
Pair your roof replacement with accurate siding estimates. Our Siding Calculator computes material quantities and costs for vinyl, fiber cement, wood, and engineered siding.