Roofing Calculator

Estimate roofing materials based on your roof dimensions and pitch. Calculate shingles, underlayment, and accessories.

🏗️ Enter Your Roof Dimensions

6/12 is most common for residential homes

More complex roofs need higher waste factor

Most codes allow max 2 layers

Planning your budget?

Read the full Roof Replacement Cost Guide 2026

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How to Calculate Roofing Materials

Our roofing calculator estimates shingles, underlayment, and accessories based on your building dimensions and roof pitch. Understanding your roof's pitch is key to getting accurate material estimates.

Understanding Roof Pitch

Roof pitch is expressed as a ratio of rise over run. A 6/12 pitch means the roof rises 6 inches for every 12 inches of horizontal run. Steeper pitches require more material because the actual roof surface area is larger than the building footprint.

What is a Roofing Square?

A "square" is 100 square feet of roof area. Shingles are sold in bundles, and it takes 3 bundles to cover 1 square for most standard shingle types.

FAQ

How many squares for a 1,500 sq ft house?

A 1,500 sq ft footprint with a 6/12 pitch needs approximately 17-19 squares (including waste), which translates to about 51-57 bundles of shingles.

How long do shingles last?

3-tab asphalt shingles last 15-20 years. Architectural shingles last 25-30 years. Metal roofing can last 40-70 years. Climate, ventilation, and installation quality all affect lifespan.

Frequently asked questions

What is a roofing square?⌄
A roofing square is 100 square feet of roof area. Roofers price materials and labor by the square, so a 2,000 sq ft roof is a 20-square roof. Shingles, underlayment, and most accessories are sold based on squares.
How many bundles of shingles are in a square?⌄
It takes 3 bundles of standard shingles to cover 1 roofing square (100 sq ft). So a 20-square roof needs about 60 bundles, plus extra for waste, starter strips, and ridge caps.
How much does a roof replacement cost in 2026?⌄
Roof replacement runs about $350 to $3,000 per square depending on material. Asphalt shingles sit at the low end ($350-$550 per square installed), while metal, tile, and slate can run $1,000 to $3,000 per square.
How do I account for roof pitch when estimating?⌄
Multiply your building footprint by a pitch factor. A low 2/12 pitch uses about 1.06, a standard 6/12 pitch uses 1.12, and a steep 12/12 pitch uses 1.42. Steeper roofs have more surface area than the footprint suggests.
How much waste should I add for a roof?⌄
Add 10-15% waste for a typical roof to cover cuts, starter courses, and ridge caps. Complex roofs with multiple hips, valleys, and dormers can need 20% or more because of extra cutting.

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