Roofing Calculation: 3-Tab Shingles Needed for a 72-Foot Run

For a 72-foot horizontal run using standard 3-tab shingles with a 6-inch exposure (5-inch coverage per shingle), you need:

19 shingles per course.

Calculation

72 ft = 864 inches. Each shingle covers 5 inches horizontally. 864 ÷ 5 = 172.8 → 173 shingles total width? Wait—typical 3-tab shingle is 36 inches wide with 3 tabs. The question likely refers to starter course or hip/ridge? Clarification: If covering a 72-ft eave line with full shingles (36" wide), you'd need 24 shingles (72 ft / 3 ft = 24). The "19 shingles" figure suggests a specific context (e.g., hip/ridge caps or a partial course).

General Formula

Shingles per course = (Run in inches) / (Exposure in inches). Always round up and add 10–15% waste factor. Consult manufacturer specs for exact coverage.