How to Measure a Roof For Shingles

Learn how to measure a roof for shingles roof like a pro. Get accurate estimates with our guide from an experienced roofing contractor.
Author picture

To provide you with the most accurate, up-to-date guides and cost figures, we gather information from a variety of local licensed contractors, pricing databases, and industry experts. Learn more.

Author picture

Reviewed by JC Sanjuan — General and roofing contractor with over a decade of experience in residential and commercial construction. He specializes in project management, quality workmanship, client satisfaction, and solving roofing challenges.

Linkedin Profile

Not sure how to measure a roof for a shingle replacement and need help figuring out where to start? Whether you’re a professional in the field or a homeowner looking to get an estimate, getting the measurements right is the first step. In this article, we’ll walk you through the process of measuring a roof, just like a seasoned roofing and general contractor would.

Steps to How to Measure a Roof for Shingles

Step 1: Research and Preparation

The first step to measure a roof is to get some basic info about the house. I like to start by looking up the home’s address on Google Maps. This gives you a bird’s-eye view of the roof so you can see its shape. It’s a great way to know a bit about the roof before you even get there.

How to measure a roof for shingles This is a photo of a house being calculated for roof measurements using Google Maps

Step 2: Visual Assessment and Sketch

After you know a bit more of your roof from Google Maps, the next step is to go assess it yourself from the ground. Take a good look at how the roof is shaped and if it has any special features like ridges or different sections. I always bring a notepad and draw the roof as best as I can to make sure I get it right. If the roof is just a simple rectangle, then that’s what I draw. Knowing the roof’s shape really well helps you get the measurements right.

How to measure a roof for shingles This is a photo of a house being calculated for roof measurements

Step 3: Safety Precautions

Safety is really important when you’re working on a roof. Before I climb up, I make sure the ladder is stable and all my safety gear is ready. I wear the right shoes and bring along a notepad, pencil, and tape measure. In this job, you can’t take chances with safety.

Step 4: Taking Measurements

How to measure a roof for shingles This is a contractor measuringridge of roof

With safety ensured, I start the actual measurement process. Here’s how it’s done:

  1. Measuring the Ridge: I begin by measuring the length of the ridge, going from one end of the roof to the other. For instance, if it measures 60 feet, I note that down.
  2. Measuring Eave to Ridge: Next, I measure from the eave to the ridge, both on one side and the opposite side. Let’s assume it’s 20 feet on each side. I jot down these measurements.
  3. Calculating Area: Let’s assume we have a rectangular roof, I multiply the length and width. In this case, it’s 60 feet by 40 feet, giving us an area of 2400 square feet.

Step 5: Detailed Measurements

How to measure a roof for shingles This is a sketch with measurements

It’s essential to account for all aspects of the roof. I also measure the sides — which are the eaves and rakes around the roof. This helps me figure out the perimeter of the house. Every detail is carefully noted on my notepad, and I label my sketch for reference.

Step 6: Crunching the Numbers

After gathering all the measurements, I return to solid ground and start working on the calculations. Here’s how it’s done:

  1. Section Breakdown: I break down the roof into sections based on its shape and features. For example, if we have three sections — A, B & C with areas of 2048 square feet, 576 square feet, and 1170 square feet, I add them up: 2048 + 576 + 1170 = 3,790 square feet.
  2. Converting to Squares: In the roofing industry, we typically work with squares, where 100 square feet equals one square. So, our 3,790 square feet becomes 37.94 squares, or 38 squares.

Step 7: Accounting for Extras

To provide a close estimate for a roofing project, it’s important to consider the waste factor and additional materials. This usually amounts to around 10 to 15 percent depending if it is a gable or hip roof, or if it has too many sections. These extra materials include ridge caps, hip caps, and starters. I add this factor to the total square measurement.

Step 8: Final Calculation

Adding the waste factor and extra materials could turn that 38 square to an additional 3 or 4 squares. The total turning out to be approximate 43 squares. This final figure is key, as most roofing professionals charge based on the price per square. Now you have a solid estimate of how much your roofing project will cost.

Conclusion

Measuring a roof accurately is the foundation of any successful roofing or general contracting project. As a seasoned roofing and general contractor, these are the steps I follow to ensure precision and reliability in my measurements.

Remember, accurate measurements lead to accurate estimates, resulting in a successful and cost-effective roofing project. If you have any questions or need further guidance on roofing matters, don’t hesitate to reach out.

There are other methods on how to measure a roof for shingles replacement. I’ll be writing other articles on those soon, so be on the look out.


Resources:

Atcheson, Daniel. Roofing Construction & Estimating. Craftsman Book Company, 2023.

author avatar
RoofGuides
Whether you need a repair or a complete replacement, we've got you covered. Our easy-to-understand guides on roofing and costs from experts will help you make the best decisions for your roofing project.
Content Overview
Are you a roofing company?
Join our pro network today.
Related Articles
roofguide logo

We’re committed to providing you with the most accurate and up-to-date information to make informed decisions about your home improvement projects. Our research process is thorough, combining local contractor insights, permit data analysis, and building code reviews to ensure our guides reflect real-world costs and comply with the latest standards. We also stay on top of industry trends and best practices by consulting with experts. By factoring in both material and labor costs, we give you a complete picture of what your roof replacement might cost.

Find a Pro Near Me:

Roofing Contractor Talking to Homeowner Should I Home During A Roof Replacement
Look Up Pro Location
Use Shift+Tab to go back