How to calculate it yourself
Bundles needed = ceil(roof_area_ft² ÷ ft²_per_bundle × 1.10). The 10% adds waste for hips, valleys, ridges, and starter courses.
Common scenarios
1,500 ft² ranch (3-tab)
15 squares × 3 bundles = 45 bundles + 10% waste = 50 bundles.
2,400 ft² two-story (architectural)
24 squares × 3 bundles = 72 bundles + 10% waste = 80 bundles.