Roof Shingle Calculator

How Many Shingles Do You Need?

Shingles are sold in bundles, and you need exactly 3 bundles to cover one roofing square (100 sq ft). The formula sounds simple — but the waste factor is where homeowners often miscalculate. A standard gable roof needs 10% waste, while a complex hip roof with multiple valleys can need 20–25% extra material.

Shingle Bundle Calculator Formula

• Adjusted Area = Roof Area × (1 + Waste Factor)
• Roofing Squares = Adjusted Area ÷ 100
• Bundles Needed = Roofing Squares × 3 (round up)

Example: A 1,800 sq ft roof with 15% waste → 1,800 × 1.15 = 2,070 sq ft → 20.7 squares → 63 bundles.

Shingle Types and Coverage

Don’t Forget Starter Strips and Ridge Cap

In addition to field shingles, you need starter course shingles along all eaves and rakes (one bundle per 100–105 linear feet), and ridge cap shingles at every ridge and hip line (one bundle covers approximately 33 linear feet).

How Long Do Asphalt Shingles Last?

3-Tab shingles last 15–25 years. Architectural shingles: 25–30 years. Impact-resistant Class 4 shingles can last 30–50 years and may qualify for homeowner insurance discounts of 20–30%.