About RoofSqft
RoofSqft is a free roof square footage calculator. It turns a few simple measurements into the numbers you need to plan a roofing job: true roof area, roofing squares, shingle bundles and a rough cost.
Why we built it
Most roof calculators online live on roofing company websites. They are built to collect your phone number, and the tool is buried under pop-ups and quote forms. We wanted a calculator that loads instantly, works well on a phone on a ladder, and never asks for personal details.
How the calculator works
Every number comes from standard roofing formulas. The footprint (with overhang) is multiplied by the pitch
multiplier √(1 + (rise ÷ 12)²) to get the sloped area. Waste is added, and the total is divided by 100
to get roofing squares. Bundles assume 3 per square. The full method is explained in our
step-by-step guide.
Who writes RoofSqft
RoofSqft is built and written by Ashish, who builds the calculator, writes every guide and checks each worked example against the calculator's tested formulas before it is published. Questions and corrections go straight to Ashish through the contact page.
Methodology and sources
Every number on RoofSqft can be traced to a formula or a published standard:
- Geometry: pitch multiplier √(1 + (rise ÷ 12)²), angle arctan(rise ÷ 12), hip length run × √(2 + (rise ÷ 12)²). The math is covered by automated unit tests.
- Material coverage: typical US product data, such as 3 bundles per square for most asphalt shingles, 1,000 sq ft synthetic underlayment rolls, 10 ft drip edge pieces and 4 × 8 ft sheathing panels. Product labels always win.
- Code references: minimum pitches, underlayment rules and sheathing fastening follow the model International Residential Code (IRC). Local codes can be stricter.
- Prices: we do not publish one national price. Cost guides show the math with example rates, so you can use your own local quotes.
How we write our guides
- Each guide answers the question in the first paragraph, then shows a worked example you can open in the calculator.
- We check every figure against the calculator and recheck guides when products or codes change. The "Updated" date on each guide shows the last review.
- We do not accept paid placements, and we never ask for your contact details.
- Spotted an error? Tell us and we will fix it.
Estimates, not quotes
RoofSqft gives planning estimates. Real roofs have valleys, dormers, skylights and mixed pitches that a simple model cannot see. Before you buy materials or sign a contract, have a licensed roofer confirm the measurements.
Contact
Found a bug or have a suggestion? Get in touch.