How to Estimate the Amount of Shingles for a New Roof in Michigan

Replacing a roof is one of the biggest home improvement projects most homeowners will ever face. Whether you’re in Southeast Michigan or anywhere else in the country, one of the first questions people ask is:

“How do I estimate the amount of shingles I need for a new roof?”

It’s a great question, because shingles are measured, sold, and priced in a way that can be confusing. And the truth is—accurate measurements are critical. Not only do they help you budget correctly, but they also protect you from unethical contractors who might inflate numbers to increase costs.

In this blog, we’ll break down:

• What a “roof square” is and why it matters

• How to measure a roof by hand

• Popular roof measurement tools like EagleView, QuickSquares, and Roofr

• Why accuracy is so important when estimating shingles

• How software verification can protect homeowners in Michigan from being overcharged

• Tips for making sure you always get a fair roofing estimate

By the end, you’ll know exactly how shingle measurements work and how to confirm that your contractor is doing things the right way.

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What Is a “Roofing Square”?

Before we get into measuring, let’s clear up the most important term:

A roofing square is a 10-foot by 10-foot area (100 square feet).

Shingles are sold in bundles, and it typically takes three bundles to cover one square. So if your roof is 20 squares, you’ll need around 60 bundles of shingles.

That’s the simple math—but things get more complex once you account for roof shape, pitch, and waste. This is why accurate measuring matters so much.

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Method 1: Hand Measuring a Roof

Hand measuring is the oldest and most traditional way of estimating shingles. It can be done by a homeowner, but it’s usually performed by roofing contractors.

Here’s how it works:

Step 1: Break the Roof Into Sections

Most roofs aren’t perfect rectangles. To get an accurate measurement, divide the roof into sections—rectangles, triangles, and trapezoids.

For example, a gable roof might have two large rectangles. A hip roof might have multiple trapezoids.

Step 2: Measure Length and Width

Using a tape measure, record the length and width of each section. If the roof is steep, it’s best to measure from the ground and use slope multipliers (more on that shortly).

Step 3: Calculate the Area of Each Section

• Rectangle = length × width

• Triangle = (base × height) ÷ 2

• Trapezoid = (base1 + base2) ÷ 2 × height

Add these together to get the total square footage.

Step 4: Adjust for Roof Pitch

Roofs aren’t flat. The steeper the pitch, the larger the surface area. To adjust for pitch, use multipliers:

• 3/12 pitch = multiply by 1.03

• 6/12 pitch = multiply by 1.12

• 9/12 pitch = multiply by 1.25

• 12/12 pitch = multiply by 1.41

For example:
If your gable roof measures 40 feet × 30 feet = 1,200 sq. ft. on the ground, and the pitch is 6/12, the actual surface is 1,200 × 1.12 = 1,344 sq. ft.

Step 5: Convert to Squares

Take the total surface area and divide by 100. That gives you the number of roofing squares.

Example:
1,344 sq. ft. ÷ 100 = 13.44 squares

You’d round up to 14 squares.

Step 6: Add Waste Factor

Most contractors add 10–15% waste to account for starter shingles, cut pieces, and valleys. Complex roofs may need 20% or more.

So in this example:
14 squares × 1.15 = 16.1 squares (round up to 17).

That means you’d need about 51 bundles of shingles.

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Method 2: Using Aerial Roof Measurement Tools

Hand measuring works, but it can be time-consuming and risky. That’s why the roofing industry now relies heavily on technology. Several companies provide satellite or drone-based roof measurement services that can generate reports in minutes.

EagleView

EagleView is one of the most trusted names in roof measurements. They use aerial imagery combined with 3D modeling to generate extremely accurate reports.

• Pros: Very precise, reduces human error, includes pitch and area

• Cons: Paid service, results take time (not instant)

Roofing companies in Michigan often rely on EagleView when providing estimates for insurance claims or large projects.

QuickSquares

QuickSquares is a faster, lower-cost version of EagleView. Instead of providing a detailed report, it gives a quick estimate of roof size based on aerial imagery.

• Pros: Fast, inexpensive, good for initial budgeting

• Cons: Less detailed, not as accurate as full reports

This is useful when homeowners just want a ballpark number before moving forward.

Roofr

Roofr is another popular tool that uses satellite imagery to measure roofs. One big advantage is that homeowners themselves can order a report.

• Pros: Homeowner-accessible, affordable, easy to use

• Cons: Still not 100% perfect, but very accurate

Many Michigan homeowners use Roofr to double-check their contractor’s measurements before signing a contract.

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Why Accurate Measurements Matter

Getting an accurate shingle estimate isn’t just about budgeting—it’s about protecting yourself.

1. Avoid Overpaying

If a roofer inflates the number of squares, they’ll charge you for materials you don’t actually need. Since shingles are expensive, even a small error can cost you thousands.

2. Prevent Shortages

On the other hand, underestimating shingles can delay your project. If your roofer runs out halfway through, your roof could be left exposed while waiting for more materials.

3. Transparency Builds Trust

Roofing is a major investment. When contractors show their math and provide measurement reports, it builds confidence with homeowners.

4. Protect Against Unethical Contractors

Unfortunately, not every roofer is honest. In Southeast Michigan, we’ve seen homeowners scammed by contractors who claim a 20-square roof is actually 25 squares. That’s a 5-square difference—15 extra bundles, which could add $1,500–$3,000 to the bill unnecessarily.

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Confirming Measurements with Software

Here’s the smart move: always confirm hand measurements with software.

When you get a roofing estimate:

1. Ask how they measured the roof. Was it hand-measured, EagleView, Roofr, or something else?

2. Request a copy of the report. Most legitimate contractors will gladly provide it.

3. Compare the numbers. If hand measurements and aerial reports differ, ask for clarification.

4. Look for consistency. If one roofer says 20 squares and another says 28 squares, something’s off.

As a homeowner in Michigan, this step can save you from costly mistakes or outright fraud.

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Local Considerations for Michigan Roofs

Roofs in Southeast Michigan face unique challenges:

• Snow load: Steeper pitches are common, which makes measuring more complex.

• Ice dams: Extra waste factor is often added for valleys and edges.

• Older homes: Many historic homes in Detroit, Dearborn, and Ann Arbor have irregular rooflines that make aerial measurements especially helpful.

Because of these factors, using both hand measurements and software confirmation is the best way to ensure accuracy.

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Example: Estimating a Michigan Roof

Let’s walk through a real-world style example:

A home in Dearborn has a gable roof with dimensions 40 ft × 30 ft, pitch 7/12.

1. Ground area = 1,200 sq. ft.

2. Pitch multiplier (7/12) ≈ 1.16

3. Actual roof surface = 1,200 × 1.16 = 1,392 sq. ft.

4. Squares = 13.92 ≈ 14 squares

5. Waste factor (10%) = 14 × 1.1 = 15.4 squares (round to 15.5 or 16)

6. Bundles needed = 16 × 3 = 48 bundles

If EagleView confirms the same 16-square measurement, you know you’ve got an accurate number. If another roofer claims 22 squares, you’d have reason to question it.

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Tips for Homeowners

• Get at least 2–3 estimates and compare measurements.

• Ask for transparency—good contractors will explain their math.

• Use software verification like Roofr if you’re unsure.

• Don’t always go with the lowest bid. Accuracy and honesty are more important.

• Understand the terms. Knowing what a “square” is puts you in control.

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Final Thoughts

Estimating the amount of shingles for a new roof doesn’t have to be a mystery. By understanding hand measurements, using tools like EagleView or Roofr, and confirming numbers, you can make sure your roofing project is fair, accurate, and stress-free.

In Southeast Michigan, where roofs face tough winters and unpredictable weather, accuracy is everything. A properly measured roof means the right amount of shingles, fewer delays, and peace of mind knowing you weren’t taken advantage of.

So the next time you’re planning a roof replacement, remember: do the math, double-check with technology, and always work with a contractor who values transparency.

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