Roofing Calculators
Estimate material quantities, fasteners, underlayment, and roof deck spacing. All roofing estimators apply pitch-corrected surface area multipliers to convert your building footprint into the actual sloped roof area.
Pro tip: Roofing materials are sold by the square or by the bundle. Always verify local pitch using a pitch gauge or slope multiplier before purchasing underlayment, shingles, or metal panels.
Shingles
Asphalt shingle bundles, squares, nails, and underlayment for any roof shape
Metal Roof
Standing seam and corrugated metal panel counts, screws, and closures
Plywood Deck
Plywood and OSB sheathing sheets, fasteners, and H-clips for roof decks
Roof Pitch
Roof angle, slope percentage, pitch multiplier, and derived rafter values
Ice & Water Shield
Ice and water shield underlayment for eaves, rakes, and valleys
Snow Load
Roof snow load analysis based on depth, density, and building code values
Featured Roofing Guides
How to Estimate Roof Shingles: A Complete DIY Estimating Guide
Master the math to calculate how many bundles and squares of shingles you need for a roof replacement. Standard bundles, waste factor, and pitch multipliers.
roofingMetal Roofing vs. Asphalt Shingles: Cost and Lifespan Comparison
A detailed comparison between metal roofs and asphalt shingles. Analyze upfront installation cost, lifespan, maintenance, and energy efficiency.
roofingHow to Estimate Attic and Roof Ventilation Requirements
A complete guide on calculating attic ventilation ratios. Intakes, exhausts, net free ventilating area (NFVA), and the 1/150 rule.
Frequently Asked Questions
What is a roofing square?
A roofing square is a standard unit of area measurement in the construction trade equal to 100 square feet of roof surface. For example, a 1,500 square foot roof is 15 squares.
How many bundles of shingles do I need per square?
Standard 3-tab and architectural asphalt shingles are packaged such that 3 bundles cover exactly 1 roofing square (100 square feet) of roof surface area.
What waste factor should I calculate for a new roof?
For a simple gable roof with few valleys or dormers, add a 10% waste factor. For a complex hip roof or a roof with multiple valleys, add a 15% to 20% waste factor to account for shingle cuts.
What is TPO roofing?
TPO (Thermoplastic Polyolefin) is a single-ply, reflective fabric roofing membrane commonly used on flat or low-slope commercial and residential buildings. Made from a blend of polypropylene and ethylene-propylene rubber, it is hot-air welded at the seams to form a watertight seal. Its white surface is highly solar-reflective, lowering cooling bills by rejecting solar heat gain. TPO is extremely durable, resists algae growth, chemical exposure, and punctures, and is typically installed using mechanical fasteners, bonding adhesives, or ballast gravel systems.
How to choose a roofing style?
Choosing a roofing style requires matching your home’s architectural design, local climate factors, and budget constraints. Classic gable roofs shed water and snow efficiently (ideal for snowy regions), while hip roofs provide superior wind resistance (great for hurricane zones). For flat or modern homes, single-ply systems like TPO are standard. Consider local guidelines, lifespan (asphalt lasts 20-30 years, metal lasts 50+), and use our Roofing Calculators to model different material square and underlayment costs before finalizing your architectural layout.
Pitch-corrected estimates
Accurate surface area
All roofing calculators apply the pitch multiplier to convert your building footprint into the actual sloped roof area. A 6:12 pitch adds 11.8% surface area; a 12:12 pitch adds 41.4%.
Complete material lists
Beyond the primary material, each calculator estimates screws, nails, underlayment, drip edge, H-clips, and closure strips so you can order everything in one trip.