The formula
Squares = footprint (sq ft) × slope factor ÷ 100, then add waste. The footprint is the area under the roof seen from above, overhangs included; the slope factor converts it to sloped surface (pitch chart).
Example: a 2,000 sq ft footprint with a 6/12 roof: 2,000 × 1.118 = 2,236 sq ft = 22.4 squares. With 12% waste: 25.0 squares to order.
Roof squares chart
Roof surface in sq ft, with squares underneath, before waste, for common footprints and pitches:
| Footprint | 4/12 | 6/12 | 8/12 | 12/12 |
|---|---|---|---|---|
| 1,200 sq ft | 1,26512.6 sq | 1,34213.4 sq | 1,44214.4 sq | 1,69717.0 sq |
| 1,600 sq ft | 1,68716.9 sq | 1,78917.9 sq | 1,92319.2 sq | 2,26322.6 sq |
| 2,000 sq ft | 2,10821.1 sq | 2,23622.4 sq | 2,40424.0 sq | 2,82828.3 sq |
| 2,400 sq ft | 2,53025.3 sq | 2,68326.8 sq | 2,88428.8 sq | 3,39433.9 sq |
| 3,000 sq ft | 3,16231.6 sq | 3,35433.5 sq | 3,60636.1 sq | 4,24342.4 sq |
Footprint is not the home’s living area: a two-story 2,400 sq ft home might have a 1,300 sq ft footprint.
Why roofers use squares
- Material: most shingles are packaged about 3 bundles per square (shingle calculator).
- Labor: crews often price tear-off and install per square, adjusted for pitch and stories.
- Comparing bids: two quotes for the same roof should be within a square or two of each other; a big gap means someone measured differently.
Rounding and waste
Order in whole bundles, so round up after adding the waste factor — typically 5–10% on a simple gable roof and 10–15% or more on hip roofs and roofs with valleys and dormers.
Questions
How many square feet is a roofing square?
100 square feet of roof surface — a 10 × 10 ft area.
How many squares is a 2,000 sq ft house?
It depends on the footprint and pitch, not the living area. A single-story 2,000 sq ft home with a 6/12 roof and overhangs is often around 24–26 squares; a two-story home of the same size has far fewer.
How many bundles of shingles are in a square?
Usually 3 bundles for 3-tab and most architectural shingles; some heavy designer shingles need 4 or 5. The wrapper states the coverage.