Roofing Calculator

Estimate roof area, roofing bundles, underlayment and optional sheathing from your roof footprint and pitch.

How it works

Roof footprint × pitch factor

DIYSum treats each section as a horizontal roof footprint, then increases that area for roof slope. A 6-in-12 pitch uses a factor of about 1.118.

Roof area = footprint area × √(1 + (rise ÷ 12)²)

After adding your allowance, the calculator rounds roofing up to whole bundles using the coverage you enter.

Does this include roof overhangs?

Only if your entered length and width include them. Measure to the roof edge when possible rather than just the exterior wall dimensions.

What is a roofing square?

One roofing square equals 100 square feet of roof area. Product packaging and contractor estimates often use squares.

Will this calculate valleys, hips or ridge cap?

No. Complex roof geometry, ridge cap, flashing, starter strips and local installation requirements should be checked separately.