Roofing Calculator

Your details

Enter the building length and width, or skip straight to a footprint area if you already know it.
The longer outside dimension of the building footprint, in plan.
ft
The shorter outside dimension of the building footprint, in plan.
ft
How far the roof projects past the walls on every side. Adds to the covered footprint. Leave at 0 to ignore.
in
Sets the default price per square and, for shingles, how many bundles cover one square.
Extra material for cuts, hips, valleys and starter rows. Simple gable roofs need about 10%; complex roofs with many valleys need 15% or more.
%
Currency
Roofing squares (with waste)Small roof, typical single-family job
18.4
True roof area1,677
Area to order (with waste)1,845
Shingle bundles56
Underlayment rolls (2 sq each)10
Roofing nails (approx.)5,904
Ridge / hip cap43
Drip edge (perimeter)160
Slope factor applied1.118
True roof area1,677
Order (with waste)1,845

Order about 18.4 squares of roofing material.

  • Your footprint becomes 1,677 ft² of true roof once the 1.118 slope factor is applied.
  • That is about 56 bundles of shingles, 10 rolls of underlayment and roughly 5,904 nails.
  • The 10% waste allowance covers cuts at hips, valleys, ridges and starter courses.

Next stepRound squares up to whole bundles, then price underlayment, drip edge, ridge cap and flashing separately.

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