Calculators · Inside the building

Roofing calculator

Squares and bundles from the footprint and the pitch.

How it is worked out

plan area × pitch factor ÷ 100 × (1 + waste) = squares × 3 = bundles

What it assumes

The pitch factor is pure geometry: √(1 + (rise ÷ 12)²). A 6/12 roof has 11.8% more surface than its footprint.
A square is 100 sq ft. Architectural shingles run 3 bundles per square.
10% waste covers hips, valleys and starter. Cut-up roofs need more.
This is the field only — flashing, ridge and underlayment are separate.

This is the same calculator that is in your Hut

Nothing on this page is a demo of the real thing — it runs the identical code. What a ToolHut account adds is everywhere the number then goes: saved against the job it belongs to, dropped straight onto a quote, and priced at a rate built from your own overhead instead of a guess.

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