Shingle Calculator
| Roof | Area | Squares | Bundles | Felt rolls |
|---|---|---|---|---|
| Small ranch, gable | 1,200 sq ft | 13.2 | 40 | 4 |
| Two-story, hip | 2,000 sq ft | 23.0 | 69 | 6 |
| Small home, gable | 1,600 sq ft | 17.6 | 53 | 5 |
| Cut-up roof, valleys | 2,600 sq ft | 31.2 | 94 | 8 |
Roofing buys and sells in its own units: the square (100 square feet of finished roof) and the bundle (a strip of shingles a worker can actually carry, about 33 square feet). Three bundles make a square for both classic three-tab and architectural shingles - the architectural bundle just weighs more, around 60 to 80 pounds against a three-tab's 45 to 60. So the whole order math hangs on one number: roof area in squares, plus a waste factor for the cuts.
Waste is where estimates die. A simple gable roof with two rectangles cuts close to the nominal count, so 10 percent covers it; hip roofs add diagonal cuts at every corner, 15 percent; and a cut-up roof full of valleys, dormers and skylights can cross 20 percent before the first bundle is opened. Valleys are the worst offenders - every course gets trimmed at an angle - which is why two roofs with identical areas can land a full pallet apart in bundles.
The shingles are not the whole pallet order. Underlayment runs under every course - No. 15 felt covers roughly 432 square feet a roll, synthetic close to 1,000 - and starter strip along the eaves plus ridge cap shingles along every hip and ridge add on top of the field count. A 20-square roof is usually 60 bundles of field shingles, 4 to 5 rolls of felt, and 2 to 3 bundles of ridge cap; forgetting the last two is the classic one-trip mistake.
How to use
- Measure the roof surface area in square feet - or take footprint area times the pitch multiplier from the roof pitch calculator if you are measuring from the ground.
- Pick the waste factor honestly: 10 percent for a plain gable, 15 percent for hips, 20 percent for a cut-up roof with valleys and dormers.
- Order in bundles (3 per square) and add underlayment: one felt roll per roughly 430 square feet, one synthetic roll per 1,000.
Frequently asked questions
How many bundles of shingles are in a square?
Three. A square is 100 square feet of finished roof and a bundle covers about 33.3 square feet, so 3 bundles per square holds for both three-tab and architectural shingles - the architectural bundle is simply heavier per strip. That 3-to-1 ratio is the whole order: 20 squares means 60 bundles, which is two full pallets of three-tab or three pallets of architectural.
How many bundles of shingles do I need for 2,000 square feet?
At 15 percent waste for a hip roof, 2,000 square feet works out to 23 squares, about 69 bundles of field shingles - call it 70 so you round up to full bundles - plus 5 to 6 rolls of No. 15 felt and 2 to 3 bundles of ridge cap. A plain gable at 10 percent waste lands at 22 squares and 66 bundles.
How much waste should I add for shingles?
10 percent on a simple gable roof, 15 percent on a hip roof, and up to 20 percent on a cut-up roof full of valleys, dormers and skylights. The waste is not padding - valley courses get angle-trimmed every row, and leftover full bundles are usually returnable unopened, so rounding up at order time costs less than a second delivery fee.
What is a square of shingles?
100 square feet of finished roof - a roofing trade unit that predates the bundle and survives because it prices the job, not the pallet. Roofers quote replacements per square; material houses sell per bundle at 3 per square. A 24-square roof is 2,400 square feet of roof and 72 bundles, and neither number has anything to do with the house footprint until pitch is applied.
Do architectural shingles cover more than three-tab?
Not per square - both install at 3 bundles per square. Architectural shingles are thicker laminated strips, so each bundle covers the same area but weighs 60 to 80 pounds versus 45 to 60 for three-tab, and costs more per square for a 30-to-50-year rated roof versus a 20-to-25-year one. Where they differ in math is weight: an architectural re-roof doubles the dead load your dumpster and your back feel.
How many rolls of underlayment do I need?
Roof area divided by coverage: No. 15 asphalt felt covers roughly 432 square feet a roll, synthetic underlayment close to 1,000. A 2,000-square-foot roof is 5 to 6 felt rolls or 2 to 3 synthetic. Synthetic costs more per roll but tears less under foot traffic, which matters on a steep roof where every re-tack is a trip down the ladder.