How this calc works

Architectural shingles run three bundles to the square; that is the conversion this calc is built on. Give it your roof area or squares and it returns bundle count — the number you actually stack on the roof and the number the supply house rings up.

Three-tab shingles are also typically three bundles per square, but some heavier laminated products run four. The calc assumes the common three-per-square; if you are running a premium designer shingle, confirm the bundle-per-square count on the wrapper and adjust.

Common mistakes

The bundle estimate covers the field only. Hip and ridge caps, starter strip, and the extra for valleys are separate line items — order them on their own or you finish the field and stall on the ridge.

The other miss is buying full bundles for a small tear-off without checking the existing layers. Two layers of old shingles change the disposal and sometimes the code path; confirm before you order anything.

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