Shingles Calculator — How Many Bundles of Shingles for a Roof?
Enter your roof footprint, pitch and waste to get squares and bundles of asphalt shingles for the job. No sign-up, no data stored.
Shingles needed
How shingle quantity is estimated
- Footprint (sq ft) = house length x width.
- Roof area = footprint x pitch factor (4/12=1.15, 6/12=1.20, 8/12=1.25, 10/12=1.35).
- Squares = roof area ÷ 100 (one square = 100 sq ft).
- Bundles = squares x bundles-per-square (3 or 4) x (1 + waste).
The pitch factor converts the flat footprint to the sloped roof surface - a 6/12 roof has about 20% more shingle surface than the footprint. Complex roofs with many hips and valleys need the 15% waste tier.
House size → shingles reference
6/12 pitch (1.20x), 3 bundles/square, 10% waste.
| Footprint | Roof area | Squares | Bundles |
|---|---|---|---|
| 20x20 | 480 sq ft | 4.8 | 16 |
| 30x30 | 1,080 sq ft | 10.8 | 36 |
| 30x40 | 1,440 sq ft | 14.4 | 48 |
| 40x40 | 1,920 sq ft | 19.2 | 64 |
| 40x60 | 2,880 sq ft | 28.8 | 96 |
Last updated: October 2026 · Cap shingles for ridge lines are extra - about 3 bundles per 100 ft of ridge. Ask your supplier for the exact product's bundle coverage.
Shingles FAQ
Three bundles per square is the standard for architectural asphalt shingles. A square is 100 sq ft of roof surface, and each bundle covers about 33.3 sq ft. Some heavy-weight shingles need 4 bundles per square - check the label.
Measure the footprint (length x width of the house), then multiply by a pitch factor: about 1.15 for a 4/12 roof, 1.20 for 6/12, 1.25 for 8/12, and 1.35 for a steep 10/12. Gable overhangs add a little more.
Ridges, valleys, hips and chimneys create cut-offs. 10% is the minimum for simple roofs; 15% is safer for complex ones with many hips and valleys. Cap shingles for the ridge are a separate item - about 3 bundles per 100 ft of ridge.
Yes - three-tab shingles run 3 bundles per square, architectural (dimensional) also 3, but heavier specialty shingles (e.g. some luxury lines) run 4 bundles per square. Match the count to the exact product you buy.
Yes - keep a bundle or two in the garage for storm repairs. Matching shingles years later is hard because dye lots change. A spare bundle costs less than a partial box from a different batch.
Related calculators & guides
How Many Bundles of Shingles for a Roof?
Square math, pitch factors and waste tiers explained.
Read the guide →