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How to Measure a Roof for Shingles

roofing problems

You’re having problems with your shingle roof and you’re thinking of redoing it? Great! But before you purchase a single shingle, you need to measure your roof properly to ensure you get the right amount. 

The size of your roof is one of the main factors when it comes to the cost, so it is important that you’re sure about it.

Below, we discuss a simple three-step process you can use to measure your roof for shingles.

Tools Needed

The following materials will be needed to measure your roof accurately:

  • A notepad
  • A tape measure
  • Pencils
  • A ladder
  • Fall prevention equipment


Before you get up on your roof, you should draw all of the planes that collectively make up your roof on a notepad so you don’t miss anything. Don’t worry about adding depth—simple yet distinct 2D shapes will be enough. Most of these will be rectangles or squares.

Don’t worry about drawing to scale—you don’t have to. Nor do you have to account for the roof’s pitch. Just draw the planes as if you were looking down on them from above.

Step One

First, you need to set up your ladder. Make sure you place the ladder’s base on level ground, and it should be about three feet away from the edge of the roof.

In this position, it should be pretty sturdy. Still, it’s good to have another person holding the ladder as you ascend it to ensure total stability. And in the unfortunate event of an accident happening, they could call emergency services.

You should also wear fall-prevention gear, such as a shock absorption lanyard and a braided rope lifeline. And wear footwear that allows you to grip the rungs well.

Lastly, always have at least three points of contact while ascending the ladder.

Step Two

Once you’re on the roof, look over the drawings made earlier to get your bearings. When you know which plane you want to start with, measure its length and then its width; record the measurements in your notepad. Do the same thing for all the other planes. 

Once you’ve got all your measurements, climb down the ladder.

Here are the formulas you’ll need to know to calculate total square footage:

Area of a Rectangle or Square:

A = L x W

Area = Length x Width

Example: 30 feet x 20 feet = 600 square feet

Area of a Trapezoid:

A = [(B1 + B2) x H] / 2 Area = [(Top + Bottom) x Height] / 2

Example: [(5 feet + 10 feet) x 6 feet] / 2 = 45 square feet

Area of a Triangle:

A = (B x H) / 2 Area = (Base x Height) / 2

Example: (10 feet x 10 feet) / 2 = 50 square feet

After you have the square footage of each plane, add them all together to get the roof’s total square footage.

Step Three

Now it’s time to figure out how many shingle bundles are needed. Most roofing squares cover about 100 square feet. So if a plane is 2,000 square feet, roughly 20 squares will be needed.

Of course, this example is just meant to give you an idea of how many shingles may be needed for a roof plane. Since shingle squares don’t always take up precisely 100 square feet, you may need more or less (depending on the size of your roof). 

Don’t Want to Measure Your Roof on Your Own? Hire Lane’s Contracting

At Lane’s Contracting, we have the tools, know-how, and manpower necessary to measure simple and complex roofs, small roofs and large roofs, and residential and commercial roofs. We also handle roof installation, repair, maintenance, replacement, and inspection.

Call us at (984) 355-9692 or check us out online if you need to get your roof measured ASAP!