Roof Shingle Calculator

Created by Maria Kluziak
Reviewed by Dominik Czernia, PhD and Adena Benn
Last updated: Sep 24, 2022

If you're looking for an easy way to estimate how much building materials you'll need for a roofing project, this roof shingle calculator is just the tool you need. With its help, the question of "How many shingles do I need" will be answered in no time.

Read the article next to the shingle calculator if, on top of getting the math done, you want to learn more about how to calculate roof shingles. You can also check the rafter length calculator to analyze the dimensions of your roof trusses!

How to use the roof shingle calculator

As you can see, our shingle calculator is relatively short and straightforward. Thanks to that, using it should be no problem! All you need to do is:

  • Input the width and the length of the roof (as presented in the illustration) in the correct fields.

  • The roof shingle calculator takes these two values and uses them to get the footprint area. The footprint is the 2D shape of a roof and is crucial for further area calculations. If you want to see it, you will find the value below roof length in the advanced mode.

  • Choose the roof pitch.

  • The drop-down menu has the 13 standard roof pitches, presented in the x:12 format. If you know the roof pitch as an angle or a percentage, you can use the roof shingle calculator's advanced mode.

  • The calculator gives you the value of the roof pitch multiplier for each of the pitches. As you can see, you cannot edit it - we included this field for information purposes only. The multiplier is a crucial part of the roof area calculation, allowing you to consider a roof's slope. If you want to learn more about it, visit our roof pitch calculator.
  • At the bottom of the "Roof dimensions" section, you will see the roof areaand roof area in squares. You can find more information in the text if you're wondering about squares in this context.

  • You will see the results at the very bottom of this roofing materials calculator! You will find the number of individual shingles and the number of bundles. You are most likely interested in the latter, as that's how shingles are sold.

  • You can adjust the default bundle size if the bundles you're buying contain a non-standard quantity. This, however, is unlikely. In the vast majority of cases, a bundle contains exactly 29 standard (12" × 36") shingles.

How to calculate roof shingles in bundles

The roof shingle calculator does the work for you, allowing you to relax and focus on other parts of your project. Still, we understand that you might feel more confident in its results if you learn how to do the math yourself! Without further ado, let's look at how to calculate roof shingles by hand. We will break the equation into smaller parts until you get all the pieces of the puzzle!

The shortest, most straightforward answer to the question of how to calculate roof shingles is this beautiful little equation:

shingle bundles = roof area in squares × 3

That is because the average bundle of shingles covers about 33.3 ft², and a square is simply an area unit covering 100 ft², so if you'd like to calculate a roof's area in squares, you'd simply divide the roof area in feet by 100 and, most likely, round it up.

roof area in squares = roof area in feet / 100.

🔎 Are you working with the metric system? Don't worry - head to our length converter 📏 to get the values in a unit you are more conformable with.

If you are interested, you can read on to the next section of this article to learn more about squares in construction. For now, though, this short explanation will do.

Now, let's break down the base roof shingle equation and learn how to measure a roof for shingles. We have the area in squares. But how do we get the area in "normal" units? To do that, we need to start with the very basic area equation:

roof footprint area = roof length × roof width.

If your roof is completely flat - that's it! But flat roofs are relatively rare, and, in most cases, they do not typically require shingles. What about a more orthodox, sloped roof? In such a case, the above equation serves to calculate the roof's footprint - the area under the roof.

To get the area of the roof with the slope included calculated, one more element needs to be added to the formula:

roof area = (roof length × roof width) × roof pitch multiplier

The roof pitch multiplier is a fixed value used specifically for calculating sloped roofs' area. It depends on the roof pitch. We included the multiplier values in the text field in our calculator - if you're interested in how it changes, click through the different roof pitches to see it!

🙋 Most shops sell shingles by the bundle, so the equations presented above should suffice for your needs. But what if you want to know the specific number of shingles? 🤔

There's no additional complicated formula for this - the bundle equation is accurate and reliable enough to simply multiply the number of bundles by how many shingles there are in one. In the vast majority of cases, that number will be 29.

What is a square in construction?

A square is an imperial unit of area used specifically in the construction business in the US and Canada. It is equal to 100 square feet.

Typically, you can expect to see squares in calculations connected with roofing, and it's also not uncommon to use it for siding materials, like wallpaper or drywall. The unit can come in handy in the case of larger construction endeavors.

Roofing materials calculator - a beginner's guide to shingles

Now that you've used the roof shingle calculator, you know how many to get. Not only that - you've also learned how to calculate roof shingles on your own. There's one question left to answer - what kind of shingles should you get in the first place? If you want to consider the total cost of your roof, check our roofing calculator, which is an excellent tool prepared for that purpose.

We also recommend that you consult a construction specialist who will help you find a material that best suits your needs. Before you do, however, consider checking out this short list of the most common shingle materials with their pros and cons - just so that you know what to expect! This should explain what roof shingles are suitable for:

1. Asphalt shingles:


  • Fireproof and waterproof. 👍

  • Flexible enough to deal with significant snow amounts (check the snow load calculator to learn more about it). 👍

  • Relatively cheap. 👍

  • Available in many shapes and colors. 👍


  • Short lifespan, meaning that they might need replacing relatively often. 👎

  • Vulnerable to temperature changes - not suitable for a climate where it fluctuates! 👎

3. Wooden shingles:


  • Aesthetic values - there's no denying they look awesome. 👍

  • They're more eco-friendly than other materials. 👍

  • Easy to power-wash mildew and mold. 👍


  • Vulnerable to fire! In fact, in some states, fire safety codes prohibit their use. 👎

  • Susceptible to damage from termites. 👎

  • Don't deal well with extreme weather conditions, especially hail. 👎

  • More difficult to replace broken shingles than in the case of most other materials. 👎

3. Metal shingles:


  • Lightweight. 👍

  • Way more durable than both asphalt and wooden shingles. 👍

  • Sunlight reflection qualities come in handy, especially in warmer climates - you might end up saving on cooling down your house a little. 👍


  • More expensive than the materials mentioned above. 👎

  • Very noisy when it's raining or hailing! 👎

  • In the case of some metals, susceptible to denting, for example by hail. 👎

4. Clay or concrete shingles:


  • Aesthetic value - arguable available in most shapes and colors. 👍

  • Non-combustible! 👍

  • Non-fading, meaning the color will likely stay as pleasing as on day one! 👍

  • With no special conditions, they can last over 50 years in great shape. 👍


  • Relatively expensive. 👎

  • Very heavy. Their weight makes it difficult to repair and exchange shingles on your own. What's more, it usually means that your roof will need extra framing to be able to support the shingles. 👎


How many shingles are in a bundle?

Typically, one bundle has 29 standard shingles with a dimension of 12" × 36". This may occasionally vary, depending on the provider. Therefore, you need to check it beforehand.

How many shingles do i need?

To find out how many shingles you need for your roof:

  1. Check the width and length of the roof.
  2. Estimate the roof pitch.
  3. Calculate the roof area based on the measured dimensions and convert it to squares.
  4. Multiply the obtained squares by 3 to find the number of shingle bundles you need.
  5. Multiply the shingle bundles by 29 (the default size of the bundle) to find the number of shingles you need.

How do I measure a roof for shingles?

You need three dimensions to find the number of needed shingles for your roof:

  1. Measure the length of the roof at the base of the roof.
  2. Measure the width of the roof, again at the base of the roof.
  3. Determine the roof pitch, which is the steepness of a roof.
  4. Use the roof shingle calculator to complete the estimations.
Maria Kluziak
Roof dimensions
Roof shingle calculator - roof dimensions
Roof width
Roof length
Roof pitch (x:12)
Roof area
Roof area in squares
Shingle bundles
Bundle size
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