Construction

Roofing Calculator

Calculate roofing squares, bundles, and material costs for your project

Quick Answer:A 40x30 ft roof at 6/12 pitch requires approximately 14.7 roofing squares (1,470 sq ft adjusted) with 10% waste in 2026, needing about 44 bundles of standard shingles at an estimated cost of $5,880-$10,290.

Roof Dimensions

Roof Length (ft)

Roof Width (ft)

Roof Pitch

Waste Factor (%)

Roofing Squares

Calculating... squares (100 sq ft each)

Total Sq Ft

Bundles Needed

Ridge Cap

Estimated Cost

Visual Comparison

Adjusted Sq Ft --

Bundles --

Cost (mid-range) --

Expert Insight 2026 Pro Tip

In 2026, asphalt shingles remain the most cost-effective roofing at $4-7 per square foot installed, while architectural shingles offer better wind resistance and aesthetics for about 20-30% more. Roof pitch significantly impacts material quantity -- a 12/12 pitch uses 41% more material than a flat roof of the same footprint. Always order 10-15% extra for waste from cuts around valleys, hips, vents, and chimneys. For steep pitches above 8/12, factor in additional labor costs of 15-25% due to safety equipment requirements and slower installation speed.

Frequently Asked Questions About Roofing

How do I calculate roofing squares for my roof?

To calculate roofing squares, first measure your roof's length and width in feet. Multiply them together to get the flat area, then multiply by the pitch factor for your roof slope (e.g., 1.118 for a 6/12 pitch). Divide the adjusted area by 100, since one roofing square equals 100 square feet. Finally, add 10-15% for waste from cuts, ridges, and valleys. For example, a 40x30 ft roof at 6/12 pitch yields 1,342 sq ft adjusted, or about 13.4 squares before waste.

How many bundles of shingles do I need per square?

Standard 3-tab asphalt shingles require exactly 3 bundles per roofing square (100 sq ft). Architectural or dimensional shingles may require 4-5 bundles per square depending on the manufacturer and style. Each bundle of 3-tab shingles weighs approximately 60-80 pounds, while architectural bundles can weigh 65-90 pounds. When ordering, always round up to the nearest full bundle and add extra for ridge caps, starter strips, and waste from cutting around vents, chimneys, and valleys.

What does a new roof cost in 2026?

In 2026, a complete asphalt shingle roof replacement costs approximately $4-7 per square foot installed, or $400-700 per roofing square. For a typical 2,000 sq ft roof, expect to pay between $8,000 and $14,000 including materials, labor, tear-off, and disposal. Premium architectural shingles add 20-30% to the cost. Metal roofing ranges from $8-14 per square foot. Factors affecting price include roof complexity, pitch steepness, number of layers to remove, local labor rates, and whether structural repairs are needed.