How to Measure a Roof for Shingles: From Ground, From Inside, and From Above

Knowing how to measure (for the full data set, see our the 2026 Aerial Roof Measurement Software Report) a roof for shingles is the difference between ordering 32 bundles and being short, or ordering 40 bundles and eating the return restocking fee. Three methods deliver useful accuracy. The ground-tape-plus-pitch method gets you within 5 to 10 percent and costs nothing. The attic-from-inside method gets you within 3 percent and takes 30 minutes. The aerial measurement service (EagleView, Hover, RoofR, GAF QuickMeasure) gets you within 1 percent for $29 to $195. Bundle math from any of the three: 3 architectural bundles per square plus 10 percent waste equals total bundle order. This is the full walkthrough.

Why roof measurement is harder than it looks

The roof you see from the ground is not the roof you are shingling. The ground footprint of a house is the horizontal projection of the roof. The actual roof surface is longer because it slopes. A 1,000 sq ft footprint with a 6/12 pitch roof has roughly 1,118 sq ft of roof surface. A 12/12 pitch roof on the same footprint has 1,414 sq ft. The pitch multiplier is the single most important variable in roof measurement, and getting it wrong is the most common cause of bundle (see our how to estimate shingles needed) shortfalls.

Beyond pitch, the geometry matters. Gable roofs are simple (two planes). Hip roofs add four planes (two large trapezoidal sides, two triangular ends). Cross-gables, dormers, valleys, and architectural details each add planes that need separate measurement. The more complex the roof, the higher the waste percentage and the more critical the accurate measurement.

Our companion piece on how to measure a roof covers measurement for any material. This article focuses on what you specifically need for shingle ordering: total square count, bundle math, and waste planning. Our how to calculate roof square footage piece covers the geometry-by-geometry breakdown.

Method 1: Ground tape plus pitch multiplier (DIY estimate)

The cheapest method, suitable for getting a rough order quantity or a sanity check on a contractor’s estimate (see our roof shingles calculator). The tools you need: a 100-foot tape measure, a level, a notebook, and either a smartphone with a pitch app or 12 inches of straight edge and a smaller level.

Step 1: Measure the footprint

Walk the perimeter of the house with the tape. For a simple rectangle, measure the long side and short side and multiply. A 50 ft by 30 ft house has a 1,500 sq ft footprint. For L-shaped, U-shaped, or more complex houses, split the footprint into rectangles and triangles, measure each, and sum.

For a typical 2-story house where the second floor footprint is smaller than the first, you are measuring the roof footprint, not the ground footprint. Walk into the second-story area you can see from below. On a house with attached garage where the garage roof and main house roof are continuous and at the same pitch, include the garage footprint. If they are different pitches, measure separately.

Step 2: Identify the pitch

Pitch is rise over run. A 6/12 pitch means 6 inches of vertical rise per 12 inches of horizontal run. From the ground or from a ladder at the eave, hold a 12-inch level against the rake (the sloped edge of the gable) and measure the vertical distance from the level (held horizontal) to the rake at the 12-inch mark. The number you read in inches is the pitch numerator. 4 inches is 4/12. 6 inches is 6/12. 8 inches is 8/12.

Smartphone apps like RoofPitch (iOS) and Pitch Gauge (Android) use the device’s accelerometer. Place the phone flat on the rake from a ladder, read the angle, convert to pitch. The apps are accurate to within 1/12 pitch increments. Our how to calculate roof pitch piece covers the math.

Step 3: Apply the pitch multiplier

The pitch multiplier converts horizontal footprint to roof surface area. Here are the standard multipliers:

Pitch	Multiplier	Example: 1,500 sq ft footprint becomes
3/12	1.031	1,547 sq ft
4/12	1.054	1,581 sq ft
5/12	1.083	1,625 sq ft
6/12	1.118	1,677 sq ft
7/12	1.158	1,737 sq ft
8/12	1.202	1,803 sq ft
9/12	1.250	1,875 sq ft
10/12	1.302	1,953 sq ft
12/12	1.414	2,121 sq ft

The math is simple: footprint times multiplier equals roof surface area. Our roof pitch chart has the full table including half-pitches.

Step 4: Convert to squares

A “square” in roofing is 100 sq ft of roof surface. Divide your sq ft total by 100. A 1,677 sq ft roof is 16.77 squares, rounded up to 17 for ordering.

Accuracy and limitations

Method 1 accuracy runs plus or minus 5 to 10 percent on simple gable roofs and plus or minus 10 to 15 percent on complex roofs with multiple planes. The error comes from approximating roof geometry as a single footprint times one multiplier when real roofs have multiple pitches, overhangs that change the projected area, and gable-vs-hip geometry that affects coverage.

Use Method 1 for: rough budgeting, sanity-checking a contractor estimate, ordering shingles for a small simple roof. Do not use Method 1 for: final ordering on a complex roof, ordering specialty shingles with long lead times, ordering for a customer where being short means a callback.

Method 2: Attic from inside (intermediate accuracy)

Going into the attic to measure the rafters gives you the actual slant length of the roof rather than the projected horizontal length. Accuracy improves to plus or minus 3 percent on most roofs.

Step 1: Measure rafter length

From inside the attic, measure along one rafter from the ridge board to the eave plate (where the rafter meets the top of the wall). On a typical 30-foot-wide house with a 6/12 pitch, the rafter length is roughly 16 to 17 feet. This is your actual slant distance.

Step 2: Measure ridge length

Measure along the ridge board from one gable end to the other. This is the run length of the roof, the horizontal distance the ridge spans.

Step 3: Multiply for plane area

One roof plane area equals rafter length times ridge length. For a simple gable roof with two identical planes, multiply by 2 for the total roof area. For a 16-foot rafter times a 50-foot ridge times 2 planes equals 1,600 sq ft of roof.

For a hip roof, the math is more complex. The four planes (two trapezoidal sides and two triangular ends) each need separate calculation. A hip roof with a 50-foot ridge length, 30-foot building width, and equal pitch on all sides has a total surface area roughly 5 percent larger than the equivalent gable roof on the same footprint.

Step 4: Add for overhangs

The rafter length you measured inside the attic does not include the overhang past the eave plate. If the eave overhang is 12 to 18 inches (typical) and the rake overhang is 6 to 12 inches, add those to the dimensions before multiplying. For a 30-foot rafter length measured inside, plus 18-inch eave overhang, the actual rafter slant is 31.5 feet.

Accuracy and limitations

Method 2 accuracy runs plus or minus 3 percent on simple gable roofs. It is less accurate on hip and cross-gable roofs where you cannot measure all planes from a single attic access point. It also requires attic access, which not all homes have, and some headroom to maneuver a tape measure.

Use Method 2 for: most DIY shingle orders, contractor estimates where the homeowner is checking the math, situations where ground measurement is impractical (heavy landscaping, tight property lines).

Method 3: Aerial measurement service (professional accuracy)

Aerial measurement services use satellite imagery, drone imagery, or both, combined with software that calculates roof geometry from the image data. Accuracy runs plus or minus 1 percent on most roofs. The deliverable is a PDF report with all plane areas, pitch values, ridge lengths, valley lengths, hip lengths, and total square count.

The 4 main providers in 2026

Provider	Cost	Turnaround	Best for
EagleView Premium	$79 to $195 per report	4 to 24 hours	Insurance claims, contractor production estimates
Hover	$29 to $79 per report	Same day to 24 hours	Contractor sales, homeowner estimates
RoofR Pro	$99 per month, unlimited reports	1 to 24 hours	Active contractors with high report volume
GAF QuickMeasure	Free for GAF Master Elite contractors	2 to 24 hours	Master Elite contractors only

EagleView is the industry standard for insurance claims and the most established. Hover added a homeowner-app workflow that lets you photograph the house with your smartphone and get a report generated from your photos rather than satellite imagery. RoofR Pro and GAF QuickMeasure are subscription or program-based.

What you get

The PDF report shows the roof as a 3D rendering. Each plane is labeled with its area in square feet, its pitch, and its dimensions. Ridges, valleys, hips, eaves, and rakes are itemized in linear feet. Total roof area in squares is at the top. For complex roofs (10+ planes, multiple pitches, dormers), the aerial report saves hours of measurement and almost eliminates ordering errors.

When the aerial service is worth it

Three situations make the $29 to $195 spend worthwhile:

• Complex roof geometry. Any roof with more than 6 planes, multiple pitches, or significant dormer area. Manual measurement gets unreliable fast.
• Specialty material with long lead time. Cedar shake, slate, tile, copper standing seam. Ordering 8 percent short on a 6-week lead time material is a much bigger problem than ordering 8 percent short on stock asphalt.
• Insurance claim accuracy. When an insurance adjuster and a contractor disagree on roof area, an EagleView report often settles the dispute.

Our piece on roof size calculator method covers the report-reading workflow and the roof material calculator piece walks through translating report data into bundle counts.

Bundle math: from squares to actual order quantity

Once you have a total square count from any of the three methods, the bundle math converts to actual order quantity. The formula varies slightly by shingle type.

Architectural shingles (the 2026 default)

Three bundles per square. A 22-square roof needs 66 bundles before waste. Apply a 10 percent waste factor: 66 times 1.10 equals 72.6, round up to 73 bundles. Add 2 to 4 extra bundles for future repairs from the same dye lot: 75 to 77 bundles ordered.

The waste factor varies by roof complexity. A simple gable with no dormers can run 7 to 8 percent waste. A typical hip roof runs 10 to 12 percent waste. A cross-gabled roof with multiple valleys and dormers runs 15 to 20 percent waste. Our shingle bundle calculator walks through the calculation by geometry type.

Three-tab shingles (legacy spec)

Still 3 bundles per square (though some manufacturers ship 4 bundles per square in 25-year three-tab). Waste factor same as architectural. Three-tab is largely phased out of new residential as of 2026 except in starter strips and budget markets.

Designer shingles (Tamko Heritage Premium, GAF Glenwood, CertainTeed Belmont)

4 to 5 bundles per square depending on the product. The thicker shingle profile is heavier and bundles less coverage per package. Check the manufacturer spec sheet on the specific product. Waste factor runs higher (12 to 15 percent) because the lengthwise cuts at hips and valleys waste more material.

Cedar shake

4 to 5 bundles per square for 18-inch shakes at 5-inch exposure. Specialty product, ordered through cedar shake distributors, not stocked at home centers in most regions.

Slate, tile, metal panel

Each has its own coverage spec. Slate is sold by piece, typical 200 pieces per square for medium slate. Tile is sold by piece, typical 80 to 100 tiles per square. Metal panel is sold by linear foot of panel run, with coverage calculated from the panel width. None follow the “3 bundles per square” rule.

Worked example: complete order for a real roof

Let us walk through a complete order for a typical 2-story home: 1,500 sq ft ground footprint, 7/12 pitch, simple gable design with attached garage at same pitch (24 ft by 22 ft, 528 sq ft additional footprint), no dormers, 2 valleys at the garage tie-in.

Step 1: Total footprint = 1,500 + 528 = 2,028 sq ft.

Step 2: Pitch multiplier for 7/12 = 1.158.

Step 3: Roof surface area = 2,028 times 1.158 = 2,348 sq ft.

Step 4: Squares = 2,348 / 100 = 23.5 squares, round up to 24.

Step 5: Architectural bundles = 24 times 3 = 72 bundles before waste.

Step 6: Waste factor (gable with 2 valleys, moderate complexity) = 10 percent. 72 times 1.10 = 79.2, round up to 80 bundles.

Step 7: Extras for future repair = 3 bundles. Total order = 83 bundles.

Step 8: Hip and ridge cap. Measure ridge length (50 ft) plus hip length (0 for pure gable). 50 linear feet of hip-and-ridge cap. Most products cover 35 to 40 linear feet per bundle. 50 / 35 = 1.5, round up to 2 bundles.

Step 9: Total shingle order: 80 bundles field + 3 bundles extras + 2 bundles hip-ridge = 85 bundles.

That order quantity, multiplied by the per-bundle delivered price for your chosen brand, gives you the shingle line on the bid. Our roofing cost per square piece covers 2026 per-bundle and per-square pricing by manufacturer.

The 6 mistakes that cause shortfalls

Even with the right method, six common mistakes cause shingle shortfalls.

1. Forgetting the garage. An attached garage is usually a separate roof plane that gets re-shingled at the same time. Measure and include.
2. Underestimating pitch. Eyeballing pitch is wrong by 1 to 2 increments more often than not. The 4/12 you guessed is often a 5/12 or 6/12. Always verify with a level or app.
3. Skipping overhang. Rafter measurements taken inside the attic do not include eave or rake overhang. Add 1 to 2 feet to each rafter and 1 foot to each ridge dimension.
4. Using a flat 5 percent waste factor. Waste varies by geometry. Cross-gables and dormers easily push waste to 15 to 20 percent.
5. Not accounting for hip and ridge separately. Hip and ridge cap is a separate product line, not included in field bundle count. Always order separately.
6. Ordering exact quantity. Always order 2 to 4 extra bundles for future repairs from the same dye lot. Asphalt shingle dye lots change between production runs, and getting a color match 5 years later on a small repair is impossible without retained inventory.

Recommended workflow by job type

Different jobs call for different measurement methods.

Job type	Recommended method	Why
DIY simple gable	Method 1 or Method 2	Free, accuracy sufficient for stock asphalt order
DIY complex roof	Method 3 (Hover)	$29 to $79 saves ordering error
Contractor sales estimate	Method 3 (Hover or RoofR)	Speed, accuracy, professional report for client
Insurance claim	Method 3 (EagleView Premium)	Industry standard, dispute-resistant
Specialty material (slate, cedar)	Method 3 + verification on site	Long lead time + high cost makes accuracy critical
Repair only (1 to 3 squares)	Method 1 with measurement at the eave	Aerial service overkill for small area

For most homeowners ordering shingles for a DIY install on a simple roof, Method 1 with careful pitch measurement gets you within ordering range. For anyone with a complex roof or working through a contractor, Method 3 pays for itself by eliminating shortfall callbacks and over-order returns. Our piece on shingle replacement covers the install side of the workflow once your shingles arrive, and the roof replacement cost calculator piece helps translate square count into total project budget.

What to do with the measurement once you have it

Knowing the square count of your roof is the foundation for everything downstream. Bid comparison: contractors quoting different square counts on the same roof are working from different measurements, and the higher count often (not always) reflects better measurement accuracy. Material ordering: bundle count, hip and ridge count, underlayment rolls, ice and water shield rolls, drip edge linear feet, all derive from the square count plus the geometric details.

Insurance claim documentation: the square count from an aerial measurement, attached to your claim, prevents the adjuster from low-balling the scope. Future repair planning: knowing your roof is 24 squares with a 7/12 pitch and 50 feet of ridge gives you the data to budget for future repairs accurately. Whichever method you use, write the numbers down and keep them with your home records. The measurement effort pays back across every roofing decision for the life of the home.