If you are planning a roofing project, the first step is learning how to measure a roof for shingles accurately. Whether you are budgeting for materials or comparing DIY costs to hiring a contractor, knowing your roof’s total square footage is essential.
Ordering too few shingles can delay your project. Ordering too many increases unnecessary expenses. Accurate measurements help homeowners in Tacoma, University Place, and throughout Pierce County plan their roofing projects with confidence.
For those who prefer precision and peace of mind, professional roof installation ensures measurements, materials, and installation are handled correctly from the start.
Quick Steps to Measure a Roof for Shingles
-
Measure the length and width of each roof plane.
-
Multiply length by width to calculate square footage.
-
Measure roof pitch and adjust surface area accordingly.
-
Add all sections together.
-
Divide total square footage by 100 to determine roofing squares.
-
Add approximately 10 percent for waste.
How do I calculate the size of my roof area?
We hope you enjoyed geometry class growing up, because you’ll need it.
Thankfully, most roofs are gable roofs—which means they consist of rectangular sections of shingles (as opposed to a more complex roof like a hip roof, which is triangular).
To calculate the size of your roof, you have a couple options.
If you’re okay with climbing onto your roof:
- Grab a ladder and climb up onto your roof
- Measure the length and width of each plane. Make sure to measure any dormers separately.
- Multiply roof length times width, then add them all together. That’s the total area of the roof, in square feet.
How to Measure Roof Pitch
Roof pitch directly affects the total surface area of your roof. Steeper roofs contain more surface area than the flat footprint of your home, meaning more shingles are required.
To measure pitch:
-
Place a level horizontally against the roof surface.
-
Ensure the bubble is centered.
-
Measure vertically from the 12 inch mark on the level down to the roof surface.
If the measurement is 7 inches, the pitch is 7/12. This means the roof rises 7 inches for every 12 inches of horizontal run.
Once you know your pitch, use an online roofing calculator to adjust your square footage and determine your true roof surface area.
Materials needed:
- Ladder
- Measuring tape
- Calculator
If you’d rather not climb onto your roof:
- Measure out the dimensions of the base of the house
- Check to see if the eaves of your roof planes extend out beyond the base of the house (i.e. overhangs). Measure that amount and add it to the length and/or width.
- Grab your ladder and climb to the edge of the roof to measure the roof pitch (or roof slope).
- Place your level against the roof and angle it so that the floating bubble is centered (i.e. so that it’s level).
- Measure the distance from the 12-inch mark of the level to the surface of the roof. This number, divided by 12, is your pitch (ex. a measure of 7 inches would mean a pitch of 7/12).
- Plug your dimensions and pitch into a pitch calculator to determine the size of your roof.
- Repeat this process for every rectangular section of your house to get your total roof area.
Materials needed:
- Ladder
- Tape measure
- Level
- Roofing calculator (online)
When you’re making these measurements, the type of roof and its condition will also come into play, especially if you’re adding a second layer of shingles later. Homeowners that engage roof installation in University Place check whether the existing layers beneath are sound enough to support new materials safely, or if stripping down is necessary.
How do I figure out how many shingles I need?
Once you know the square footage of your roof, you’re ready to determine how many shingles you need to buy.
Squares
The standard unit of measurement for shingles is a roof “square”—which is actually 100 square feet (10 ft. x 10 ft.) of shingles.
So to determine number of squares you need, divide the total square footage of your roof by 100 (ex. – 3,000 sq. ft. / 100 = 30 squares of shingles).
A pro tip: budget about 10% of extra shingles to account for shingle waste due to trimming.
Bundle
Roof shingles are sold by the bundle and by the square. The average asphalt shingle square weighs about 400 pounds, so roof squares are split up into smaller bundles of shingles.
The number of bundles can vary slightly based on the packaging, but typically it’s three bundles per square.
How Much Do Roof Shingles Cost?
Shingle prices vary by manufacturer, product line, and regional market conditions. Below are general material estimates per roofing square:
-
Asphalt shingles: approximately $90 per square
-
Metal roofing: $275 to $400 per square
-
Composite shingles: around $400 per square
-
Wood shingles: $350 to $500 per square
-
Clay tiles: $300 to $1,000 per square
Material cost represents only part of your total project investment. Labor, tear off, underlayment, flashing, disposal fees, and ventilation upgrades can significantly impact final pricing.
Many homeowners in the Tacoma area measure their roof first to estimate material costs before requesting a professional quote.
Considering whether adding another layer is viable? Our blog post What Are the Pros and Cons of Layering Roof Shingles? compares layered vs full tear-off options, helping you decide what’s best based on roof age, structural load, and long-term performance.
What are the basic tools and materials I need to install a new roof?
A list of tools and materials you could use to install a roof would be very long. But here are the basics for a standard installation of three-tab asphalt shingles on a residential roof.
Materials
- Roofing nails
- Roofing sealant
- Self-adhesive waterproof underlayment
- Flashing for vents and valleys
- Drip edge
- Asphalt shingles
- No. 15 or No. 30 felt paper
Tools
- Extension ladder
- Roof harness
- Chalk line
- Caulk gun
- Air hose or air compressor Hammer
- Roofing stapler
- Straight edge
- Tin snips
- Utility knife
- Saw
- Scaffolding and tarpaulin
- Work gloves
How long should I expect a roof installation to take?
An experienced team of roofers can typically install a new roof on an average-sized home (i.e. 3,000 square feet of roof) in a day. But that can vary based on a variety of factors: size of your home, type of shingles, weather, and accessibility.
If you go the DIY route, you’re most likely looking at longer timelines—in some cases significantly longer. The timeline of a DIY roof installation can vary even more widely based on additional factors that include work and family schedules, expertise, manpower and more.
Should You Re Roof Your Home or Hire a Contractor?
Many homeowners measure their roof to determine whether to install shingles themselves or hire a licensed roofing contractor.
DIY roofing may reduce short term labor costs. However, there are important risks to consider:
-
Fall hazards and safety risks
-
Warranty limitations if shingles are installed incorrectly
-
Building code compliance
-
Proper flashing and waterproofing installation
-
Western Washington’s heavy rainfall, which requires precise installation
Hiring a professional contractor typically involves higher upfront cost but reduces long term risks such as leaks, structural damage, and premature roof failure.
Before deciding, weigh both short term savings and long term protection.
Need a Roofer in Tacoma?
If measuring your roof feels overwhelming or you would prefer a professional assessment, ACME Roofing can help. Our team provides detailed roof measurements, material estimates, and professional installation throughout Tacoma, University Place, Puyallup, and surrounding communities.
Call (253) 215-1398 or request a free estimate to ensure your roofing project is measured and installed correctly from the beginning.
Frequently Asked Questions
How accurate do roof measurements need to be?
Roof measurements should be as precise as possible. Small miscalculations can result in ordering too few shingles or overspending on excess materials.
How do I convert square footage into roofing squares?
Divide total roof square footage by 100. One roofing square equals 100 square feet of surface area.
How much extra shingles should I order?
Most professionals recommend adding at least 10 percent extra to account for trimming waste and ridge cap installation.
Does roof pitch increase the number of shingles needed?
Yes. Steeper roofs have greater surface area than flat measurements suggest, which increases the total number of shingles required.
Can I measure my roof without climbing on it?
Yes. You can measure the home’s footprint from the ground, calculate pitch using a level and ladder, and use a roofing calculator to determine total surface area.