What Is A Square In Roofing?

For your upcoming roofing project, you may have found out that estimates or materials are measured in squares. That may not help much if you do not know what a square in roofing is. Not only do you need to be able to answer, “What is a Square in Roofing?” but you probably also want to know how to determine how many squares your roof is.

A square in roofing is 100 square feet of the roof. It does not have to be a literal square and 4’ x 25’ is one square, just like 10’ x 10’. For example, a 20 square roof is a total of 2,000 square feet of surface area.

In this article, you will find information about the parameters of a square in roofing and why roofs are measured in this way. You will also learn how to measure and calculate the square footage of your roof and what you can expect to pay per square for a roofing job.

What Is A Square In Roofing

What is a Square in Roofing?

A roofing square is a form of measurement but is different from the total square footage. Instead, a single square is equal to 100 square feet. This measurement can also be used to measure tarp, shingles, tiles, and other roofing materials.

A square in roofing is used to determine the cost of materials and labor. It makes it easier to calculate materials than it would be if it was merely total square footage. Not only can a roofing square be beneficial for roofing and construction professionals, but it can also help you measure the cost of doing your own roofing work, like re-shingling.

The use of squares in roofing meant there is a standardized unit and method to measure the layout, shape, and size of a roof. One thing to keep in mind is that a roofing square does not always have to be a square shape. It can be any shape that amounts to 100 square feet. Therefore, a 10’ x 10’ area is one square, but so is a 20’ x 5’ area on the roof.

A roof’s square footage is not the same as the home’s square footage. This is because of a couple of different factors. First, there are often areas of a home that do not count towards the total square footage but do have roofing on them and should count towards the number of squares on a roof. In addition, the slope of the roof can add some square footage that would not be calculated in the total if you merely went by the home’s square footage.

How to Figure Out Square Footage of a Roof?

How to Calculate Squares on a Roof

There are multiple factors and things to keep in mind to ensure that you calculate the area of your roof correctly.

Measure Roof Square Footage

When preparing to measure your roof, you first want to make sure that you have a sturdy ladder that is tall enough and stable. Measuring your roof can be dangerous if you do not have good equipment. This also means that you need to wear shoes that will give you enough traction to prevent you from slipping.

To measure the roof, use a measuring tape. Divide the roof into planes and measure the length and the width of each plane. If you have a rectangular roof with a single peak, then there may only be two planes. However, an extending garage, covered patios or other areas, skylights, dormer windows, and other elements can divide the roof into more planes.

Be sure to measure twice. If you mess up, you do not want to go ahead and buy the materials because you may end up wasting money by getting too much or having to order again if you do not order enough materials initially.

To calculate the square footage, you will multiply the length and width of each plane. Then, you add all the totals together. The sum of the area for each plane is the total square footage of the whole roof. Now, you can take this total square footage and divide it by 100 to determine the number of squares. Therefore, every 1,000 square feet is 10 squares.

Since it can be difficult to measure from the peak along the sides to get the exact area accounting for pitch, it can be easier to measure the roof as a flat surface initially. Then, you can calculate the pitch to determine the surface area of the roof itself.

Taking Pitch Into Consideration

The pitch of the roof is something that must be considered if you want to get an accurate number of squares for your roofing project. If you do plan on measuring yourself, make sure to be careful. Some roofs will have different pitches for different areas depending on the number of slopes and peaks.

Once you have the amount of pitch estimated, climb onto the roof with a two-foot level. Place the level on the peak of the roof extending outwards above the slope. Make sure that it is centered so that 1 foot will extend out in each direction from the peak. Also, make sure that the bubble is centered so that you have a level and accurate measure. When it is level, take a tape measure and measure the distance between the end of the level and the roof.

This makes a triangle where you will have a single foot as one side and the distance from the roof up to the level for another. This will give you the amount that the roof pitches because it will tell you for every foot of the roof, the pitch will increase the height amount. For example, if you have 6 inches of height and 12 inches of length, then the pitch is 6/12. This means that for every 12 inches of roof, the height increases by 6 inches.

Once you have the pitch, take the number and simplify it down. For 6/12, it would simplify to ½. Then, square that result. For ½ that means you would end up with ¼. Add a whole to that fraction, which is the bottom number added to the top number to get 5/4 or 1.25. Finally, find the square root of that number to get 1.118. This number can be multiplied by the flat square footage if you measure it without accounting for slope to give you the total area that the roof surface covers.

How to Calculate Squares on a Roof: Example

Since it may still be somewhat confusing, let’s look at a detailed example so that you can learn where to plug each number in. Let’s start with a roof that looks like this:

Measure Roof Square

For a house that is this shape, you will want to divide it into rectangular planes. There are a few ways to do this, but for this example, we will take the entire left side of the house and the entire right side of the house. This will leave the central area as the third plane.

The left side measures 20 feet, but only the entire length from the edge of the left side to the edge of the right side is measured at 30 feet. Since we only want the left side, we have to subtract the length of the center area, 8 feet, by the total length, 30 ft, to get 22 ft. This means that the total area of the left side is 20 ft by 22 ft or 440 square feet.

Doing the same for the right side, we also have one edge at 20 ft. Then, we have the width at 4 ft. This equals 80 square feet.

Finally, the central area has a length of 8 feet. The width is equal to 20 feet – (4 + 4 ft). Therefore the entire central area is 12 feet by 8 feet or 96 square feet.

Adding all the areas up, we get 440 + 80 + 96 = 616 square feet. This is the area if you have a flat roof. However, to figure out the number of squares, you have to account for pitch. Using the method above, let’s say we get a pitch of 8/12. You can simplify that to ⅔. Add a whole number to it to get 5/3 or 1.67. Then, find a square root (it isn’t cheating to use a calculator!) and you get 1.29. This is the number that you will multiply by the total square footage.

Accounting for pitch, the total square footage is 1.29 x 616 = 794.64. However, to calculate the squares, you will have to divide that number by 100 to get 7.95. This is the number of squares and to account for any additional materials, you can round it up to 8 squares. Rounding up can also allow you to accommodate for any overhang or other discrepancies.

Roof Square Footage Calculator

While it is good to know how to do the calculations yourself, there is a much easier way: a calculator! You can just put in the length, width, and pitch of the roof. Once you plug them in, it will calculate the squares and amount of supplies that you will need to redo the roof. You can even use it to calculate only a portion of the roof to determine the number of materials needed for a smaller project.

How Many Bundles in a Square?

How Many Bundles Of Shingles Do I Need

Shingles are purchased by the bundle and different types of shingles are different sizes and the bundles contain different amounts. Standard shingles measure 12” x 36” and come in bundles of 29. Each bundle will therefore cover around 33 square feet.

This means that there are 3 bundles of standard shingles per square of the roof. This is similar to other types of shingles that are different sizes, even if they contain fewer shingles per bundle. However, it is still best to double-check because sometimes there are some discrepancies.

How Much Does Roofing Cost Per Square?

How Much Does Roofing Cost Per Square

The amount you will pay for materials per square can depend on several factors. The type of materials and the scope of the project can make the cost range drastically. However, you will typically be looking at $300 to $500 per square for shingle installation. You may pay a little more for specialty shingles or tiles.

Factors that Affect Cost Per Square

To better understand how much your roofing project might cost, it is important to know how different factors can influence the total cost of the job. Then, you can determine the estimated cost per square for your roofing project.


Okay, so the amount of materials increases per size, but the size can also impact the cost of materials and labor per square despite always being the same amount of shingles required. Typically, when you buy more materials, you can get them at a discounted price. Labor is often done similarly. While it may not save you much per square for a larger project, it may be worth it to do more than you planned if you will have to complete the other parts of the roof soon anyway.


So we already discussed how pitch can alter the number of squares on a roof. However, it can also influence labor costs. A very steep roof makes installation more difficult whether you are doing it yourself or hiring someone. This means it can take more time and money to accomplish work for identical square footage.


Shingles are an affordable option, but different kinds can vary in cost. You may also want to choose tiles or some other material. This is a huge factor in determining the total cost of a roofing project.

Scope of Project

Just installing shingles will be cheaper than having to remove old materials before installing new ones. Even if you do it yourself, this will take more time. If you hire someone, the change in cost could be significant. The same goes for the roof itself and how easy it is to properly access the different portions of the roof.


Finally, the warranty is something that will factor into the total cost per square. If your old roofing materials are still under warranty, you may get a substantial discount. The amount that is covered and the way you can take advantage of a warranty depends on who the warranty is with. If you purchase a new warranty for the materials or project, you will want to remember to keep that information handy for the future. Always look at what the warranty covers to see if it will be worthwhile.


Construction and roofing professionals use squares when discussing the scope of a roofing project. This may seem awkward at first, but once you understand the reasoning behind it and how to calculate the roofing squares, you may find that it makes sense and is more convenient than dealing with larger numbers as total square footage.

Knowing the squares of a roof before a project that takes pitch into account can help you estimate the total cost for a project and can also help you compare quotes if you plan on hiring someone for the roofing project.

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