How To Calulate How Meltal Roofing Needed

November 30, 2025

2 min read

To calculate how much metal roofing is needed, you measure your roof size in square feet, then divide by 100 to get the total number of squares. Most metal roofing comes in 100-square-foot sections called squares. According to RubyHome, roof installation costs range from $4 to $40 per square foot, and for a 1,700 square foot roof, you would need between 17 and 20 squares of material. Metal roofing is a smart choice because according to RubyHome, metal roofs last 40 to 80 years, making them much longer lasting than asphalt shingles. Let’s walk through the simple steps to figure out exactly how much metal roofing your home needs.

What Is a Roofing Square?

A roofing square is a simple unit of measurement used by all roofers. One square equals 100 square feet of roof space.

This makes math easy. If your roof is 1,700 square feet, you need 17 squares of metal roofing. If your roof is 2,000 square feet, you need 20 squares. The measurement keeps contractors and homeowners on the same page.

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How to Measure Your Roof Size

You can find your roof size a few different ways. The easiest is to measure your home’s footprint (length times width) and multiply by your roof’s slope factor.

Your home’s footprint is the ground area. If your house is 40 feet long and 30 feet wide, that’s 1,200 square feet. But roofs slant upward, so they cover more space. A pitched roof might be 1,500 to 1,800 square feet depending on the angle. According to the National Association of Home Builders, the average U.S. roof size is 2,647 square feet, or about 26.47 squares.

You can also hire a roofer to measure for you. Many offer free estimates.

Calculate Metal Roofing Needed

Here is the simple formula:

Step 1: Measure your roof in square feet
Step 2: Divide by 100
Step 3: Add 10% for waste and cuts
Step 4: Order that many squares of metal roofing

Example: Your roof is 1,800 square feet. Divide 1,800 by 100 = 18 squares. Add 10% = 1.8 extra squares. Order 20 squares total.

Metal roofing costs vary by type. According to RubyHome, standing seam metal panels cost $10 to $17.05 per square foot, while corrugated metal costs $5.50 to $11.50 per square foot. For a 2,000 square foot roof with standing seam panels, you would spend about $20,000 to $34,100 installed.

Why Add Extra Material?

Always order 10% more metal roofing than you calculate. Roofers cut pieces to fit valleys, vents, and roof edges. Some pieces get damaged during installation. According to RubyHome, DIY projects can save about 50%, but mistakes lead to higher long-term costs from roof problems.

Professional roofers know how to cut metal efficiently and handle waste properly. Metal roofing is an investment that lasts decades, so getting the right amount from the start matters.

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Contact a qualified professional roofer for expert guidance on roof repair, replacement, or installation.