Shingle Count Calculator
Calculate how many roofing shingles you need for your roof.
Enter roof area and pitch to get the number of shingles and bundles required.
Roofing shingles are sold by the square in North America. One roofing square equals 100 square feet (9.29 square meters). Most asphalt shingle bundles cover approximately one-third of a square, meaning you need 3 bundles per square.
The basic process for calculating shingle count:
Step 1 — Calculate the flat roof area (length × width for each roof section).
Step 2 — Apply a pitch multiplier. Roof pitch affects the actual surface area compared to the flat footprint. A steep roof has more actual surface area than a flat projection of the same footprint.
Pitch multipliers:
- Flat / 1:12 pitch: 1.00
- 2:12: 1.02
- 3:12: 1.05
- 4:12: 1.08
- 5:12: 1.13
- 6:12: 1.18
- 7:12: 1.24
- 8:12: 1.30
- 9:12: 1.37
- 10:12: 1.45
- 12:12: 1.56
Step 3 — Add waste factor. Standard practice is to add 10–15% for waste, cuts, and overlap. For complex roofs with many valleys, hips, or dormers, add 15–20%.
Step 4 — Convert to squares: Divide total square feet by 100.
Step 5 — Convert to bundles: Multiply squares by 3 (for standard 3-tab shingles) or by 4 (for dimensional/architectural shingles, which cover about 25 sq ft per bundle).
Imperial: Most roofing in the US is measured in feet and squares. Metric: In metric countries, coverage is stated per bundle in square meters. Most bundles cover 2.4–3.1 m² depending on shingle type.
Always order a minimum 10% extra beyond your calculated amount. Running short mid-project can be a problem if the same batch or colour is unavailable. Unused bundles from an unopened package can often be returned to the supplier.