Calculating the square footage of a roof might sound like a head-scratcher, but it’s a skill every homeowner should have in their toolbox. Whether you’re planning to replace shingles or just curious about your roof’s size, let’s unravel the mystery of how to calculate the square of a roof without diving into the math abyss.

The Simple Way to Calculate Square Footage:

No rocket science here, just plain and easy steps:

1. Divide Your Roof into Shapes:

Think of your roof like a jigsaw puzzle. Divide it into sections of simple shapes – rectangles, squares, triangles, and trapezoids. For example, if your roof looks like a rectangle and two triangles, treat them separately.

2. Measure the Length and Width:

For each shape, grab a measuring tape. Measure the length and width. Imagine you’re sizing up a picture frame – how tall and wide it is.

3. Square Footage for Rectangles and Squares:

To find the square footage of a rectangle or square section, multiply the length by the width. It’s like calculating the area of a room. For example, if a rectangle is 20 feet long and 10 feet wide, it’s 20 x 10 = 200 square feet.

4. Square Footage for Triangles:

Triangles are half of a rectangle. To find their square footage, multiply the base (the bottom) by the height (from the base to the tip), and then divide by 2. Picture slicing a sandwich diagonally – it’s half.

5. Square Footage for Trapezoids:

Trapezoids can be trickier but not by much. Add the lengths of the parallel sides (the top and bottom), multiply by the height (the perpendicular distance between those sides), and then divide by 2. It’s like finding the area of a road sign – wider at the top, narrower at the bottom.

6. Add It All Up:

Once you’ve calculated the square footage for each section, add them together. It’s like putting the puzzle pieces back to get the full picture of your roof’s square footage.


Calculating the square footage of your roof isn’t as complicated as it might seem. It’s all about breaking it down into manageable sections, measuring, and applying straightforward math. Whether you’re planning a roofing project or just satisfying your curiosity, knowing how to calculate your roof’s square footage is a valuable skill for any homeowner.

So, the next time you wonder how to calculate the square of a roof, remember these simple steps. It’s like solving a puzzle – piece by piece, until you have the full picture.


As a civil engineer and roofer, I love to share the experience that I have gained through the last couple of years. In the roofing industry, practical experience is a very crucial fact that can help you a lot. Hence, I want to help you with my blog.

Write A Comment