Free roofing calculators that show their work

Roof pitch, area, squares, shingles, metal panels and cost. Every tool shows the formula, a worked example and the assumptions, so you can check the numbers before you order or sign.

Quick roof pitch check

Most-used calculators

Shingle calculatorBundles, starter, ridge cap, underlayment, drip edge and nails in one go Roof pitch calculatorRise and run to x/12, degrees and multipliers Roof area calculatorFootprint plus pitch to true square footage Metal roofing calculatorPanel count, cut length and screws Roof replacement costPlanning ranges by material, with sources Roofing squaresWhat a square is and how many you need 2-minute roof checkNine questions: repair or replace? Your estimate, explainedLine items, why bids differ, what to ask

Built for three kinds of roof people

Homeowners

Find out how big your roof really is, what the pitch means, and what a fair price range looks like before contractors come out.

Cost estimator · 2-minute roof check · Estimate explained · Roofing calculators

DIYers

Measure from the ground, get exact bundle and nail counts, and cut rafters right the first time.

Measure a roof · Bundles · Rafters

Roofers and estimators

Fast takeoff math for the truck or the office: waste, underlayment, edge metal, cap and starter, nails and panel cut lists.

Waste · Underlayment · Edge & cap

Every common roof pitch

Angle, multiplier, rafter lengths and area tables for each pitch: 1/12 · 2/12 · 3/12 · 4/12 · 5/12 · 6/12 · 7/12 · 8/12 · 9/12 · 10/12 · 11/12 · 12/12. Or see the full pitch-to-degrees chart.

Why RoofGenius

Shows the math. Formulas, worked examples and tables on every page, so results can be checked by hand.
No signup. Calculators run in your browser. Nothing you type is sent anywhere.
Roofing calculators since 2001. RoofGenius has published roof pitch and estimating tools for over two decades, and the site was rebuilt from scratch in 2026.

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