SkyRoof Measuring

Roof Measurements

What is the standard unit for roofing measurement?

A roofing square is a unit of measurement for calculating the size of a roof and is equivalent to 100 square feet. The larger unit is useful for calculating the amount of material needed for a roof. It’s common to calculate the size of your roof in “squares”, and then order an additional 15% in backup materials.

How do you calculate the rise and run of a roof?

Calculate the roof rise using the figures for unit rise and total run. Multiply your figure for unit rise by your figure for total run to get the total rise. Using the example, it would be six inches times 13 feet. The total roof rise in the example equals 78 inches.

How do I calculate a rise?

Subtract the difference in elevation between two points on a hill to calculate the rise. The elevation could be determined by an altimeter or you could use a topographic map. As an example, you might read 900 feet at the top of a hill and 500 feet at the bottom, so subtract 500 from 900 to get a rise of 400 feet.

What are the 4 types of slopes?

Slopes come in 4 different types: negative, positive, zero, and undefined. as x increases. The slope of a line can also be interpreted as the “average rate of change”.

How to measure your roof area from the ground

A more accurate way to calculate the area of the roof than using Google Earth is to get outside to estimate the roof pitch and the base area of the property. Using these two figures, we can get a good idea of the shingle roof’s square footage and estimate your asphalt shingles’ needs and costs. This DIY technique can be helpful, especially if you are not comfortable getting on your roof, or if you have limited access to it.

Ground measures only work well for a gabled roof, since there are usually just two main rectangular pitches to calculate area for. For more complex roof shapes, like hip roofs, you’ll need to work with a roofer or measure from on top of the roof itself to calculate its total area.

Roof Measurement Report :

The Roof Measurement Report provides a detailed analysis of your roof layout and all the critical dimensions. Our full color report provides the detailed lengths, pitch and areas of every surface plane and edge. This report saves your time and enables accurate roof estimates for a roof repair or replacement. This is a professional grade report used for use by licensed roofing contractors or insurance companies. You will receive the report in .PDF format by email within 1-3 days. Follow us!


  • Images: 1 Orthogonal (overhead), 4 Oblique (birds eye), and 1 Street View (where available), all in full color.
  • Roof Measurements and Areas: includes Eaves, Rakes, Ridges, Hips and Valleys, and edges are all separately measured and identified.
  • CAD style drawings with colored lines identifying every type of roof edge and area for each plane/section.
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Measure My Roof

Measure the length of the roof at its base along one side of your house. Use a ladder, if necessary, to get the most accurate measurement. Measure along the roof’s angle to get the width of your first roof area. Multiply the length by the width to get the area in square feet. Follow us for more details please.

Sky Roof Measure provides accurate roof measurements in .esx format, for use with Xactimate, at affordable prices. We now also provide wall measurement reports in PDF format .

Call us : (315) 926 1777

Email: [email protected]

Our service is quick and easy to use.  Sign up for a free account today and ordering is as easy as 1, 2, 3!

  1. Enter the address where you need a measurement on the home page, and confirm the location on the satellite map view.
  2. Choose the type of report you need – commercial or single family home and/or wall report – and add any special instructions.
    • Add your reference number or claim ID to the order for easy tracking.
    • Let us know if you have special requirements, such as including secondary structures on single family home orders.
  3. Confirm your order and checkout.  You can also order multiple reports on a single invoice including an entire campus. 

Most customers pay by credit card.  Let us know if you need to pay by check.

How to use the google maps area calculator tool to measure a roof

Special precautions must be taken when measuring the area of a roof. The images that appear on google maps are often at a slight angle, which combined with the angle of a roof can cause errors. For this reason it is best to outline the roof at points which are all at the same elevation. On a simple house for instance you would only click on the corners of the roof and not on any points along the peak as that would cause an error. After measuring the area of the footprint you can estimate the actual roof area based on the angle of the roof. Similarly if you using the area calculator tool to measure a roof with multiple levels, you should do the individual section separately. The google maps area calculator is not 100% accurate. Do not rely on this tool as your only resource in making important decisions.

How to Get Your Satellite Roof Measurements

You’re a few simple steps away from your aerial roof measurements (and a better back!):

    • Enter Your Details: Give us your name, email, and phone number so we can contact you.
    • Enter Your Address: Let us know which roof to measure.
    • Leave Notes: Tell us to exclude the garage or anything else we should know before sending your measurements.
  • Confirm Your Address: Hey, we just want to know we’re measuring the right house!

That’s it! Just proceed to the payment page (if necessary), and you’ll get your measurements instantly. See, wasn’t that way better than spending all day on the roof in the hot sun?

From there, you’ll create your free toolbox account where you’ll have access to your measurements and a ton of tools to make your roof project easier, cheaper, and faster.

Aerial measurement

Measure My Roof

To do this, measure the length and width of each plane on the roof, including dormers. Then, multiply length x width to get the square footage of each plane. Finally, calculate your roof’s total square footage by simply adding the square footage of each of the planes together.

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How to Determine Your Roof Pitch

The next step is to measure the pitch (also referred to as the roof slope) of the roof deck. You’ll need to figure out the vertical distance (also known as the rise) over a 12” horizontal segment (also known as the run). Record these values as roof rise over run, with the vertical measurement listed first and the horizontal second.

It’s important to keep in mind that the roof pitch will be dramatically different for homes with a flat roof than homes with a steep roof.

Roof pitch affects the actual area of the roof. Depending whether the roof area is measured horizontally (possibly from a drawing or photograph), a correction factor is necessary to determine the actual area of the roof. Given pitch and a horizontal area measurement, multiply the horizontal area by a correction factor corresponding to pitch, provided in the table below, to determine the actual area of the roof to be used in the Roofing Material Calculator. While it is possible to estimate the amount of necessary materials using only the total roof area measurement, as can be seen from the table, depending how large the pitch of the roof, the actual area of the roof can differ by up to 2.236 from the measured total area at a pitch of 24/12. As such, while it can be cumbersome, measuring the area and pitch of each part of the roof and multiplying by the corresponding correction factor will result in the most accurate estimate of necessary roofing materials.

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Typical Slope Correction Factors:

PitchAngleMultiply By PitchAngleMultiply By
1/124.8°1.003 2/129.5°1.014

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If you want to get the exact area measurement for your roof, you can follow these steps:

  1. Once you have your roof’s pitch, divide the number by 12. (For example, if your roof’s pitch is 4 in 12, you would divide 4 by 12. This would yield 1/3.)
  2. Next, square your result. (If your number is 1/3, squared would yield 1/9.)
  3. After that, add 1 to your number. (1/9 + 1 = 10/9.)
  4. Next, figure out the square root of your new number. (The square root of 10/9 is 1.05.)
  5. Next, use your measuring tape to measure the length of your house. (Be sure to include overhangs.)
  6. After that, measure the width of your house. (Be sure to include overhangs.)
  7. Multiply your house length by your house width to get the area. (For example, 40 feet x 30 feet = 1,200 square feet.)
  8. Next, multiply the area by your roof’s pitch. (1,200 x 1.05 = 1,260 square feet.)
  9. To allow for hips, ridges, and waste, add 10% of your final number for a gable roof and 17% of your final number for a cottage roof. (Your total number would be either 1,386 or 1,474 square feet.)
roof blueprint

How to Measure a Roof From the Ground

If you’re planning work on a roof and don’t have the building plans, taking preliminary measurements from the ground allows you to approximate the roof area and estimate some costs. Measuring hip roofs, dormer roofs or roofs on hillside homes from the ground requires experience and special equipment. But, you can measure a gable or flat roof from the ground with the help of an assistant.

Method 1: Counting asphalt shingles to measure your roof area from the ground.

Most asphalt shingles are three feet wide with three tabs. Each tab is got 5 inches of reveal. So by counting these in digital photos you can come up with pretty reliable dimensions. If there is any doubt on the shingle dimensions, you can calibrate the method by measuring a typical shingle in a lower, accessible location.

Method 2. Pythagorean Theorem.

Measure the horizontal run of the roof surface from the ground (‘a’ in the third figure below). Then count the number of shingles to the peak of the roof. Multiple the number of shingles times the width of each shingle (which you can measure at ground level) to get ‘b’ in the figure below. Then calculate the line length of the roof (‘c’ in the figure) using the Pythagorean Theorem; c = square root (a squared + b squared). It is also easy to calculate the roof angle by taking the inverse tangent of b divided by a.

With these simple tricks you can measure your roof area from the ground.  

Roofing Calculator

How Roof Pitch is Calculated

To accurately calculate the area of your roof, you must first determine its slope, or pitch. A roof’s pitch is determined by how much it rises vertically for every foot it runs horizontally. Thus, a moderate “6 in 12” roof pitch means that the roof rises 6 inches vertically for every 12 horizontal inches it runs. A “12 in 12” pitch is a steep, 45-degree angle roof. See the image below for more explanation on rise, run and pitch.

Three Easy Ways To Measure Your Roof’s Pitch

Pitch Measurement Method 1

Roof Pitch Calculator

1. On a ladder beside the roof, place the level a foot or so up the roof, hold it level, and measure from the 12-inch mark on the level’s bottom, straight down to the roof. If this distance measures 4 inches, you have a 4 in 12 pitch; 8 inches and you have an 8 in 12 pitch.

Pitch Measurement Method 2

Roof Calc

2. On a ladder at the gable end of your house, place the level against the gable trim, flat against the side of the house. Now measure from the 12-inch mark of the level up to the bottom edge of the gable trim. This distance is the roof’s rise.

Pitch Measurement Method 3


3. In the attic, place the level against a rafter with the 12-inch mark on the bottom of the rafter. Measure from the end of the level up to the bottom edge of the rafter. That is the roof’s ris


measure roofs

How do I measure my roof for shingles?

To estimate how many shingles you’ll need, first estimate the total square footage of your roof’s surface. To do this, measure the length and width of each plane on the roof, including dormers. Then, multiply length x width to get the square footage of each plane.

How do you calculate shingles for a roof?

Roof surfaces are measured in “squares”. A roofing square is equal to 100 square feet of the roof. To determine the number of squares on the gable roof example in this post, divide its total of 2400 square feet by 100 (2400 ÷ 100 = 24). This means you would need 24 squares of shingles to cover that roof.

How many bundles of shingles do I need calculator?

The most accurate way to calculate how many bundles of shingles you’ll need is to get up on the roof and measure each roof plane. If all the roof planes are rectangles, you simply need to multiply the length times the width of each plane to get the square footage; then you will add up the square footage of each plane.

How many shingles do I need for a 12×12 roof?

How Many Bundles of Shingles Will You Need. The average bundle of shingles covers 33.3 ft2, so three bundles of shingles are needed per square.

How many bundles of shingles do I need for a 10×10 roof?

Three bundles to a square is most common, which applies to most three-tab strip shingles and some lightweight laminated shingles. Heavier three-tabbed shingles and laminated shingles require four, or sometimes five, bundles to cover a square.

How many bundles of shingles do I need for 2000 square feet?

The number of bundles or squares you need will depend on the surface area of your roof, and its pitch or slope. For example, a 2,000 square foot roof will require 20 squares or 60 bundles. A professional will likely purchase slightly more materials than necessary to ensure there is extra material if needed.

How many bundles of shingles do I need for 1500 square feet?

This means you would need 240 squares of shingles to cover that roof. The most common type of shingle, called a three-tab or strip shingle, is generally packaged three bundles per square.

How many shingles do I need for 1000 square feet?
House by Square FootRoof by Square FootRe-Roofing Cost*
1,2001,265$4,500 – $6,500
1,5001,581$5,500 – $8,000