Roofing Calculator

Estimate roof area, roofing squares, and shingle bundles from footprint and pitch.

Results will appear here.

Planning estimate only. Verify dimensions, waste, coverage, product specifications, and local requirements before purchasing materials.

This tool runs completely in your browser. No data is transmitted, stored, or logged.

Transparent methodology

How this calculator works

Reviewed July 2026

Formula

Adjusted roof area = footprint area × √(1 + (rise ÷ 12)²). Roofing squares equal adjusted area ÷ 100, before waste is added.

Worked example

A 40 ft × 25 ft footprint with a 6-in-12 pitch is adjusted by the slope factor, then increased by the selected waste allowance.

Frequently asked questions

What is a roofing square?

A roofing square is 100 square feet of roof surface.

Is footprint area the same as roof area?

No. A sloped roof has more surface area than its horizontal footprint.

Does this replace a roof measurement report?

No. It is a planning estimate; complex roofs should be professionally measured.

Privacy: Inputs and results stay in this browser. Any future sponsored recommendation or advertisement will be clearly labeled and kept separate from the calculation.