How to figure square footage for shingles

Q: How do I measure my roof for shingles?

To estimate how many shingles youll need, first estimate the total square footage of your roofs surface. To do this, measure the length and width of each plane on the roof, including dormers. Then, multiply length x width to get the square footage of each plane.

Highlights

A package of shingles is called a bundle.
Table of Contents Show
There are between 15 and 29 shingles in a bundle.
A bundle typically covers 33 square feet regardless of shingle type.
You’ll need to account for waste, which is material that is cut off and overlapped.
Divide total square footage by 33 to find how many bundles you need.
You'll also need roof underlayment and trusty nails.

Get quotes from up to 3 pros!

Enter a zip below and get matched to top-rated pros near you.

If you’re repairing or replacing a roof, it’s important to know how many shingles you’ll need to get the job done. Different shingles have different measurements. Typically shingles come in three bundles to a square. This handy guide discusses how many shingles are in a bundle, how many shingles you need depending on the type of shingle you're using, and the number of shingles you'll need per square foot.

How Many Shingles Are in a Bundle?

Photo: colorburst100/ Adobe Stock

There are anywhere between 15 and 29 shingles in a bundle. Typically, a bundle covers 33 square feet. Bundles usually weigh the same regardless of the number of shingles because they’re designed to be carried by one person.

Here are a few examples of bundles depending on the size of shingle you need:

Shingle Type	Number of Shingles Per Bundle
Standard Size Shingles (12”x36”)	29
Asphalt 3-Tab Roof Shingles	26
Architectural Shingles	21

How Many Bundles Are In a Roofing Square?

Roofs are measured in roofing squares, with each square representing 100 square feet of roof. Since a bundle offers around 33 square feet of shingles, you’d need roughly three bundles per square. To find how many squares your roof has, you can divide the total square feet of your roof by 100. Keep in mind that the square footage of your roof is not the same as the square footage of the house—it’s about 50% to 60% more on a one story home, after factoring in the garage. You’ll also need to account for a waste factor, which is typically between 10% and 20% on most roofs. Roof waste is material that is overlapped or cut off during installation.

How Do I Calculate How Many Shingles I Need?

Once you've determined the square footage you need to cover, you can figure out the number of bundles you need by dividing the total square footage by 33.

Example: if you have 2,000 square feet of roof to cover, that means you'd need about 60 bundles (2,000 divided by 33 is about 60).

How Many Shingles Do I Need Per Square Foot?

You will need anywhere from one to two shingles per square foot, depending on the type and size of shingle you choose. As stated, a bundle will cover about 33 square feet of roof regardless of type, so the question is not how many shingles you need (because they come in different sizes) but how many shingle bundles you need. Just take the overall square footage and divide by 33 to get that answer, then add on the waste factor of between 10% and 20% of your roof’s size.

Consider Roofing Slope

The slope of your roof impacts the number of shingle bundles you’ll need. Houses with steeper roofs have more roof area to cover, so make sure you measure the roof properly to know the actual square footage.

A roof slope, or pitch, is measured by the rise of the roof in feet over the run of the roof in feet. Most homes’ pitches fall somewhere between 3/12 and 12/12. These numbers help find the roof pitch multiplier, which then allows you to find the total surface area by multiplying it times the area covered by your roof.

To save some time and brain power, you can refer to the table of common roof multipliers by roof pitch below.

Roof Pitch (rise over run)	Roof Pitch Multiplier
3/12	1.031
6/12	1.118
9/12	1.250
12/12	1.414

Does the Type of Shingle Impact How Many I Need?

A bundle typically covers 33 square feet regardless of type of shingles you have.

So even though, say, you get fewer architectural shingles in a bundle than a standard shingle, those architectural shingles cover a larger area, so the square footage is about the same.

It’s a good idea to include a few extra bundles when ordering for your roofing project for a variety of reasons. Complex roofs especially require additional shingles to cut to fit over tricky roof edges and corners.

Extra shingles will come in handy for repairs down the road, after your roof weathers strong winds and precipitation. An extra bundle or two also helps keep your property matching, should you need additional roofing touch ups on a shed or other outbuilding on your lot.

“If you decide to keep some extra shingles, store them flat in an area that is not exposed to sunlight,” says Ami Feller, Expert Review Board member and owner of Roofer Chicks in New Braunfels, TX. “Shingles will dry out over time and become brittle. This will help your shingles remain usable for a longer period of time. You should especially keep a few extra if you ordered an unusual color or type of shingles—sometimes shingles are discontinued.”

What Other Supplies Will I Need?

It’s best to hire a professional roofer to handle any shingle replacement job, although homeowners with extensiver roofing experience can handle it themselves.

Roof underlayment will be laid on your roof before any other materials, so it’s vital that you have an appropriate amount. You will need at least a square of underlayment for each roofing square your home has. You should also account for some waste with underlayment. Each row has to overlap the one before it, so it takes between 5% and 10% more than the square footage.

Of course, you’ll want your shingles to stay put. That’s where nails are a necessity. Each shingle should receive at least four nails. You can determine how many nails you need by multiplying the number of shingles needed (which you’ve calculated earlier) by four.

Some dimensional shingles have a higher wind rating if you use six nails, so you should check the manufacturer specifications before ordering.

However, if you live in an area susceptible to inclement weather, it’s beneficial to up the ante and opt for six nails per shingle. You would use the same formula, substituting in six nails instead of four.

How many bundles of shingles do I need calculator?

This makes it relatively easy to figure out how many shingle bundles your roof requires: simply multiply the number of roofing squares by three. If your roof's area were equivalent to about 20 roofing squares, then you would need about 60 bundles of shingles.

What is the formula for the square footage of a roof?

Multiply your house length by your house width to get the area. (For example, 40 feet x 30 feet = 1,200 square feet.) Next, multiply the area by your roof's pitch. (1,200 x 1.05 = 1,260 square feet.)

How do I measure my roof for shingles?

To estimate how many shingles you'll need, first estimate the total square footage of your roof's surface. To do this, measure the length and width of each plane on the roof, including dormers. Then, multiply length x width to get the square footage of each plane.

How many bundles of shingles do I need to cover 320 square feet?

There are between 15 and 29 shingles in a bundle. A bundle typically covers 33 square feet regardless of shingle type. You'll need to account for waste, which is material that is cut off and overlapped. Divide total square footage by 33 to find how many bundles you need.