Understanding Roofing Squares: Calculation and Conversion

In the world of roofing, the term “roofing square” is frequently used to measure and estimate the size of a roof. It is essential to understand what a roofing square is and how to calculate it accurately. This article will provide a comprehensive guide to help you figure out roofing squares and convert them into square feet.

What is a Roofing Square?

A roofing square is a unit of measurement used in the roofing industry to determine the size of a roof. One roofing square is equal to 100 square feet (10 feet by 10 feet) of roof area. It is important to note that a roofing square is not a square foot but rather a unit of measurement representing 100 square feet.

How to Figure Roofing Squares?

To calculate the number of roofing squares required for a particular roof, you need to follow these steps:

  1. Measure the length and width of each individual roof plane in feet.
  2. Multiply the length by the width for each roof plane to obtain the area of each plane in square feet.
  3. Add up the areas of all the roof planes to get the total roof area in square feet.
  4. Divide the total roof area by 100 to determine the number of roofing squares needed.

For example, let’s say you have a roof with two planes: one measuring 40 feet by 30 feet and the other measuring 20 feet by 20 feet. The calculations would be as follows:

Roof Plane 1: 40 feet x 30 feet = 1,200 square feet

Roof Plane 2: 20 feet x 20 feet = 400 square feet

Total Roof Area: 1,200 square feet + 400 square feet = 1,600 square feet

Number of Roofing Squares: 1,600 square feet / 100 = 16 roofing squares

Conversion: Roofing Squares to Square Feet

If you already know the number of roofing squares and want to convert it into square feet, you can use the following formula:

Number of Square Feet = Number of Roofing Squares x 100

For instance, if you have 10 roofing squares, the conversion would be:

Number of Square Feet = 10 roofing squares x 100 = 1,000 square feet

Common Roofing Measurements

Roofing measurements are typically rounded up to the nearest roofing square. Here are some common measurements:

  • 1 roofing square = 100 square feet
  • 1 bundle of shingles covers approximately 1/3 of a roofing square (33.3 square feet)
  • 1 square of underlayment typically covers 200 square feet

Understanding these measurements can help you estimate the amount of materials needed for your roofing project accurately.


Knowing how to figure roofing squares is crucial for any roofing project. By understanding the concept of a roofing square and following the calculation steps, you can accurately estimate the size of a roof and determine the number of roofing squares required. Remember, one roofing square is equivalent to 100 square feet, and this conversion can help you plan and budget for your roofing needs effectively.