SANGOBUILD Product Page

Downspout and Gutter Sizes ( Guide)

By Sam Wasson

Join the 4,617 people who have received a free, no-obligation quote in the last 30 days

Enter details in under 3 minutes

Join the 4,617 people who have received a free, no-obligation quote in the last 30 days

All products and services featured are independently selected by our editors. However, when you buy something through our retail links, we may earn an affiliate commission.

When choosing the best gutters for your home, consider gutter size, as it affects how well they&#;ll handle water flow. Gutter size also impacts material costs, gutter performance, and which gutter guards will fit your system. To help you identify the size gutter you need for your home, we&#;ll cover standard gutter sizes, how to calculate your roof&#;s square footage and more.

 

Compare Quotes From Gutter Specialists

Just answer a few questions, and we&#;ll take care of the rest.

 

What Are the Standard Gutter Sizes?

Gutter size refers to the width of the gutter. The most common gutter size is 5 inches, but some homeowners opt for 6-inch gutters to handle more rainfall. There are also 4- and 7-inch gutters, but they are less common. Homeowners who live in areas with heavy rainfall or who have steep roofs may opt for larger gutters to handle the increased runoff.

Size by Gutter Type

Most modern American homes use K-style gutters with a standard size of 5 inches. Older homes, or those in areas with frequent downpours, may have half-round gutters, which are typically 6 inches wide. We&#;ll outline the most common types of residential gutters and their average sizes below. 

K-Style

K-style, or ogee, gutters are the most common style for American homes. They get their name from their side profile, which has a K shape and resembles crown molding. These gutters are durable, reliable, and easy to install. K-style gutters are typically 5 inches wide, but homes with large roofs may require 6 inches.

Half-Round

Half-round gutters are the second most common choice for American homes and have a drum-like shape. These gutters are often paired with metal materials, such as zinc or copper, making them heavier and more expensive than K-style gutters. However, their classic look makes them popular with homeowners who want an old-world aesthetic. These gutters don&#;t direct water as effectively as K-style gutters, so they&#;re typically 6 inches wide. Smaller homes or areas with less rainfall can have 5-inch variants.

 

 

What Size Gutter Do You Need for Your Home?

The most important factors in determining the size of your new gutter system are your roof&#;s square footage and pitch and your area&#;s rainfall rate. The larger your roof and the steeper its slope, the more water flow your gutters must be able to handle. This corresponds to how large your gutters need to be. Your contractor or gutter installer typically manages this process, but it&#;s important to understand how these calculations work if you want to do a DIY installation or price your gutter system beforehand.

Below, we&#;ll break down each step for calculating your roof&#;s gutter size needs. 

Calculate Your Roof&#;s

Square Footage

Most roofs have multiple sections, often referred to as gutter drainage areas. You need to measure each of these sections individually to find your roof&#;s total surface area. For example, a gable-end roof has two sections that meet at the ridge. You would multiply each side (section of the roof) by length and width.

Account for

Roof Pitch

Once you have the surface area of each roof section, you must account for the pitch factor. A roof&#;s pitch factor is the incline of the section, which acts as a multiplier for its total area. Note that some instructions refer to the pitch factor as a roof pitch multiplier. To obtain each section&#;s pitch factor, you need its rise over run, or slope. This number is measured by how many vertical inches a surface rises for every horizontal foot it extends (runs).

You can calculate the roof slope on your rooftop or from within your attic. Measure 1 foot horizontally (this is your run) inward from the roofline along the wall. From that point, measure the vertical height (your rise) to the top of the roof. This number is written as rise: run. If your roof pitch is 4 inches high by 1 foot long, it&#;s written as 4:12. Once you have this number, you can calculate its corresponding pitch factor, which is the length of your roof&#;s rafter divided by the run. There are calculators online that can quickly determine this factor based on roof pitch, or you can use the following table.

Roof PitchPitch Factor

1:12

1.

2:12

1.

3:12

1.

4:12

1.

5:12

1.

6:12

1.118

7:12

1.

8:12

1.

9:12

1.25

10:12

1.

11:12

1.

12:12

1.

Now that you have your pitch factor, you can use it to find your true roof area. Multiply the square footage of each roof section by its pitch factor. For example, if the right section of your gable roof is 40 feet long by 25 feet wide with a pitch factor of 1.05, your equation would be 40 x 25 x 1.05 = 1,050. Once you have the total square footage of each section, you can add them together to find your total gutter drainage area.

Calculate Rainfall

After calculating the total drainage area of your roof, it&#;s time to account for your region&#;s rainfall. You&#;ll need your region&#;s rainfall rate&#;the amount of rain that falls in inches per hour. You can search for the city nearest you on this form from the International Code Council to find your region&#;s rainfall.

Multiply your region&#;s rainfall rate by your gutter&#;s total drainage area. Let&#;s assume you live outside of Charlotte, North Carolina, and have a total drainage area of 2,100 square feet. The Charlotte region has a rainfall rate of 3.7, meaning your surface area multiplied by rainfall rate equals 7,770. Refer to the following table to see which type and size of gutter suits your home based on this number:

Gutter StyleGutter SizeRainfall Adjusted Roof Size

K-style

5-inch

5,500 or less

K-style

6-inch

For more information, please visit pvc gutter size.

7,900 or less

Half-round

5-inch

2,500 or less

Half-round

6-inch

3,800 or less

 

 

What Size Downspouts Do You Need?

When installing your gutter system, it is essential to understand how many downspouts you&#;ll need and where to position them. Downspouts are the vertical sections of gutter that transport water away from the home. If you don&#;t place your downspouts correctly, water will pool around your foundation and cause erosion.

Downspouts come in several shapes, including spiral, box, and round. K-style gutters are typically fitted with box downspouts, which can come in two size categories: 2-inch by 3-inch and 3-inch by 4-inch. Five-inch K-style gutters use 2-inch by 3-inch downspouts. Six-inch gutters use 3-inch by 4-inch downspouts.

Half-round gutters use rounded downspouts. Round downspout sizes range from 3 inches to 6 inches in diameter. Depending on rainfall, most homes require 3-, 4-, or 6-inch diameter downspouts.

How Many Gutter Downspouts Do You Need?

A home typically requires one downspout per 25 to 35 linear feet of gutters. However, homes with heavy rainfall or multiple tiers of gutter systems require additional downspouts to drain properly.

 

 

Our Recommendation

Finding the right gutter size for your home can be difficult, especially when calculating your roof pitch manually. However, it&#;s an important step toward having a functional drainage system. A professional roofing contractor or gutter installation company will handle the complex task of gutter sizing. You might also want to consider researching the best gutter guard companies for gutter guard installation that occurs simultaneously with the installation of new gutters.

 

Compare Quotes From Gutter Specialists

Just answer a few questions, and we&#;ll take care of the rest.

 

How We Chose the Top Gutter Guard Providers

We researched and analyzed dozens of gutter guards and gutter guard companies to create an in-depth review methodology. We formulated a rating system based on the factors homeowners find most important. We evaluated each provider&#;s gutter guard design and aesthetics, service offerings, customer service and communication, quote process, warranties, and financing options. 

We created a separate rating system for DIY-installed gutter guards sold on retailer sites. We evaluated these guards based on their quality of materials, aesthetics, communication, warranty, customer reviews, and cost.

We evaluated each provider&#;s reputation using independent, third-party sites such as the Better Business Bureau (BBB) and Google My Business pages. For products, we analyzed the customer reviews on whichever online retailer primarily hosts the product.

Gutter Size FAQ

Does gutter material factor into its size requirements?

Technically, no, the size requirements of your home are not affected by your gutteru#;s material. However, certain materials may not perform as well as others in certain climates. For example, while aluminum gutters work well for most locations, itu#;s lightweight and areas with extreme winds or heavy snowfall will want something heavier, like steel or copper.

What are the standard gutter sizes?

The most common sizes for gutters are 5 inches and 6 inches.

What are the advantages and disadvantages of 6-inch gutters?

The advantage of 6-inch gutters is that they can handle more water. However, they are heavier and more expensive than 5-inch options.

How do I maintain my gutter system after installation?

After installation, maintain your gutter system by cleaning your gutters regularly. Even the right-size gutters for your home wonu#;t function well if they aren&#;t regularly cleaned. Clogs, blockages, and overflows lead to water damage, warped fascia, eroded foundations, and saturated lawns.

Gutters are a part of your home that you probably don&#;t think about often &#; especially if they&#;re installed correctly and doing the job they&#;re meant to do. But, if you need to replace your gutters, they&#;ve probably been on your mind, and you might not know where to begin. 

You might be surprised to discover that not all gutters are the same size. Coincidentally, choosing the right-sized gutter is the best place to start when purchasing new gutters, so we&#;ll tell you about standard gutter sizes and how to pick the proper selection for your home. 

What Are the Standard Gutter Sizes?

For residential gutters, the standard size is 5 inches. Homeowners can also opt for 6-inch gutters, which hold significantly more water. Gutters 5 inches wide are 3 ½ inches deep, while gutters 6 inches wide are 3 ¾ inches deep. 

While 5-inch gutters are the standard size, some homeowners opt for larger ones. 6-inch gutters are more expensive, but they can handle large amounts of water and are less likely to get clogged. 

What Size Gutter Is Best for My Home?

In most cases, 5-inch gutters will best serve a home. If you&#;re wondering if your home will benefit from 6-inch gutters, there are a couple of factors to consider:

• The square footage of your roof

• The pitch of your roof

• The geographical area you live in

Follow these steps to figure out the proper gutter dimensions for your home:

Calculate the square footage of your roof:

• Measure the length and width of each area of your roof.

• Multiply each length and width to determine the square footage of that area.

• Add those square footage measurements together to get the total square footage of your roof. 

Calculate the pitch of your roof.

• Hold a level horizontally, with one end touching the roof&#;s surface.

• Measure 12 inches along the level from the end that&#;s touching the roof.

• Then, measure the space from the roof to the bottom of the level. 

• This number will be your pitch. 

Multiply your roof&#;s square footage by a number determined by the roof&#;s pitch:

• Pitch of 0 &#; 3 inches: no multiplier

• Pitch of 4 &#; 5 inches: multiply the square footage by 1.05

• Pitch of 6 &#; 8 inches: multiply the square footage by 1.1

• Pitch of 9 &#; 11 inches: multiply the square footage by 1.2

• Pitch of 12+ inches: multiply the square footage by 1.3

Use the resulting number to choose the right-sized gutter:

• If your number is between and , 5-inch gutters are best. 

• If your number is higher than , 6-inch gutters are best. 

Lastly, consider the geographical area that you live in. If you don&#;t encounter a wet season or intense rainfall, 5-inch gutters should suffice. If your area is known for intense downpours, you could benefit from installing more oversized 6-inch gutters.

Need Professional Help With Gutters?

Installing high-quality gutters is one of the best ways to protect your home from water damage. Improper gutters can result in flooded basements, wet ceilings, and rotted roof sheathing. If you don&#;t want to tackle this challenging project yourself, contact an experienced roofing professional. 

At Werner Roofing, we know that no roof is complete without a gutter system to help control and direct water flow safely off your roof. We provide full-service gutter installation and repair to ensure your home&#;s exterior is always in excellent condition. If you have questions about your gutter system or think you might need a repair or installation, don&#;t hesitate to call Werner Roofing. We&#;re here to help!

Give us a call at 616-844- or contact us online today for your free, no-obligation quote.

Are you interested in learning more about kill moss on asphalt shingle roof? Contact us today to secure an expert consultation!