Roofing Calculator

Roofing Calculator is a fast, clean tool for estimating how much roof you have and how many shingles you need — completely offline. Enter your building footprint, pick a roof pitch, set a waste allowance, and get roof area, squares and bundle counts the moment you type.

WHAT YOU CAN DO
• Enter footprint length and width in feet or meters
• Choose a roof pitch from 1/12 to 12/12 (rise per 12 of run)
• See the slope factor and pitch angle update instantly
• Set your own waste percentage (10% is typical)
• Read off roof area, number of squares, shingle bundles and area-with-waste

HOW IT WORKS
The app models a simple gable roof. The slope factor — the square root of 1 plus (rise over 12) squared — converts your flat footprint into the actual sloped surface area. One square equals 100 square feet of roof, and asphalt shingles run about three bundles per square, so the math stays on the scale roofers actually quote.

WORKED EXAMPLES
A built-in Examples tab shows presets — a garden shed, a single-storey house, a steep cottage roof and a metric bungalow — so you can see how size, pitch and waste change the numbers before running your own.

LEARN AS YOU GO
A Learn tab explains, in plain language, what roof pitch and the slope factor are, what a "square" means, and why you always buy more material than the bare roof area.

ESTIMATE ONLY
These are rough planning estimates for a simple gable roof. They do not account for valleys, hips, dormers, overhangs or local building code. Always confirm measurements and material quantities with a qualified roofing professional before ordering or building.

PRIVACY
The app collects no personal data and works fully offline — your inputs never leave your device. Ads are served by Google AdMob, which may use an advertising identifier as described in Google's policies.

Light and dark themes, a tiny download, and no clutter. Download Roofing Calculator and plan your roof with confidence.

Recent changes:
improve app performance