RoofingCalculator.ioFree Roofing Calculators
Each calculator answers one question. Pick the one that matches your project, enter a few measurements, and you get numbers you can take to a supplier or a roofer.
Roof Cost Calculator
Enter the footprint, pitch and material to get roof area, squares, materials and an installed price range. Start here if you are replacing the whole roof.
OpenRoof Pitch Calculator
Turns rise and run, an angle or a level reading into pitch, degrees and an area multiplier.
OpenShingle Bundle Calculator
Counts the bundles, starter and ridge cap you need for shingles or cedar shakes.
OpenRoof Ventilation Calculator
Turns attic size into required vent area and the number of ridge, soffit or box vents.
OpenGutter Cost and Size Calculator
Works out gutter length, downspouts, cost and the right gutter size for your rainfall.
OpenFlat Roof Calculator (EPDM, TPO, PVC)
Estimates membrane area, seams, flashing and installed cost for rubber and single-ply roofs.
OpenEPDM Roof Cost Calculator
Prices an EPDM rubber roof by thickness, color, attachment, insulation and tear-off, per foot and per square.
OpenTPO Roof Cost Calculator
Prices a TPO roof by thickness, attachment, insulation and tear-off, per square foot and per square.
OpenMansard Roof Cost Calculator
Prices the steep sides and flat top of a mansard, with dormers, tear-off and curb flashing.
OpenMetal Roof Panel Calculator
Counts panels, screws, trim and closures for standing seam or exposed-fastener roofs.
OpenRoof Sheathing Calculator
Counts plywood or OSB sheets, underlayment rolls and ice and water shield.
OpenRepair or Replace Calculator
Compares a repair with a new roof by age, damage and cost per year of life left.
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Which roofing calculator do you need?
Use the roof cost calculator if you are replacing the whole roof. It gives you a price range for the full job. If you are ordering materials, the shingle, metal panel and sheathing calculators turn your roof area into bundles, panels, sheets and rolls, with waste built in. For a specific problem, such as a hot attic, overflowing gutters or a leaking flat roof over the garage, use the ventilation, gutter or flat roof calculator.
Every calculator runs in your browser, needs no account and shows its math so you can check it. Prices are 2026 US national averages, so local quotes will come in above or below them. The roofing guides explain where these numbers come from.