🏠 Roofing Calculators
📝 JusTheTool Editorial | 🔄 Last reviewed: July 21, 2026 | 15 tools
Roofing estimates go wrong for one reason above all others: people calculate from the building's footprint instead of the sloped surface. A 12:12 roof has 41% more surface than the ground it covers. Every calculator here applies the pitch multiplier automatically.
Start with your pitch if you do not already know it, then work through squares, bundles, panels, or rafters depending on the material.
Most used in this category
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How many bundles of shingles you need per square, how to measure your roof with the pitch multiplier, plus underlayment, waste, and a worked example. - Roof Shingles Calculator: Figure Squares, Bundles & Materials
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Free roof pitch calculator. Convert rise and run into pitch (x/12), angle in degrees, grade, and rafter slope multiplier. Pitch-to-degrees chart included. - Roof Slope & Pitch Calculator (Degrees Chart)
Free roof slope calculator. Convert rise and run into slope percentage, grade, ratio (1:X) and degrees — for roof slope, ADA ramps, and pipe drainage. - Roof Pitch Chart: Pitch to Degrees Conversion
Complete roof pitch conversion chart: every pitch from 1/2:12 to 24:12 in degrees, slope percentage, and rafter multiplier — plus a reverse degrees-to-pitc - Gutter Calculator
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Free sheathing calculator for roofs and walls. Enter dimensions to get exact 4x8 OSB or plywood panel count with waste factor. Instant results. - How Many Squares Is My Roof?
A roofing square is 100 sq ft. Learn how to measure your roof in squares from the ground using the footprint and pitch multiplier, with a full example. - Complete Roof Pitch Guide: Chart, Angles & How to Calculate
Complete roof pitch guide with chart showing all common pitches (4/12, 6/12, 8/12), angles in degrees, and step-by-step how to measure and calculate roof p
Before you order
- Measure twice, at the building. Plans and reality diverge. A wall drawn at 30 ft is often 30 ft 1 in once framed.
- Add a waste factor. Every calculator here exposes one. The defaults are industry-standard ranges, not guarantees — complex layouts need more.
- Confirm code locally. We cite the model IRC where a limit applies. Your jurisdiction amends it, and your building department has the final word.
- These are estimates, not quotes. Useful for budgeting and comparing options; not a substitute for a supplier quote or a licensed professional.
How we derive every figure is set out on our methodology page, including the code sections and manufacturer specs behind each constant.
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