PitchCalc
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Roof Area Calculator

Convert a building footprint and pitch into sloped square footage and roofing squares. This page does not output shingle bundles.

Convert footprint into roof area

This page reports sloped square footage and squares. It does not add waste or bundles.

Measurements stay in your browser

Example house size (30 × 40 ft). Replace it with your footprint.

ft

Horizontal outside dimension.

ft

Horizontal outside dimension.

/ 12

Common US pitches. 6/12 is a typical house.

Using 6/12

ft

Added to all four sides.

Roof area calculator FAQ

Footprint, slope, and squares — without mixing in material waste.

What is the difference between footprint and roof area?

Footprint is the horizontal rectangle the building covers. Roof area is that rectangle multiplied by the pitch multiplier, which accounts for slope. A 1,200 sq ft footprint at 6/12 is about 1,342 sq ft of roof surface.

Does this page include shingle waste?

No. This calculator reports sloped area and squares only. Add waste and convert to bundles on the shingle calculator so the two tasks stay separate.

How do I calculate roof square footage?

Measure length and width, add overhangs if needed, multiply to get the projected area, then multiply by √(1 + (rise ÷ run)²). Divide the sloped area by 100 to get roofing squares.