How To Measure Your Home’s Gutters

Ready to measure your gutters like a pro? Our guide makes it easy and accurate.

Written by Mike Miller Updated 10/29/2024

Whether your gutters need a fresh coat of paint or extensive repairs, the first step is measuring them. Knowing how to measure gutters allows you to purchase the right amount of materials to replace, repair, or paint gutters yourself. It also helps you budget for the cost of new gutters or gutter guards and get accurate quotes if you decide to hire professional gutter installers. Our guide explains the tools you’ll need, the steps for measuring, and how to select the right gutters.

Gutter Types and Sizes

Before measuring, it helps to know the common gutter types and understand what matches your home’s drainage needs.

Popular Gutter Styles

The most common styles are K-style and half-round. K-style gutters have a flat bottom and back with a decorative front, resembling crown molding. Half-round gutters, as the name suggests, have a semicircular profile. Some homes may also feature box-style gutters or custom fascia gutters.

Common Gutter Sizes

Residential gutters typically come in 5-inch and 6-inch widths. The right size for you depends on factors like your roof’s square footage and local rainfall. Here’s a quick breakdown of what each size can handle:

5-inch K-style gutters: For roofs up to 5,520 square feet.
6-inch K-style gutters: Handles roofs up to 7,960 square feet.
5-inch half-round gutters: Suitable for roofs up to 2,500 square feet.
6-inch half-round gutters: Works with roofs up to 3,840 square feet.

Materials Used in Gutters

Gutters come in various materials, each with pros and cons:

Aluminum: Lightweight, rust-resistant, and affordable.
Copper: Attractive, long-lasting, but pricey.
Steel: Strong and durable but may rust if not maintained.
Vinyl: Inexpensive and easy to install but less durable in extreme weather.

Tools and Materials Needed

Measuring gutters is relatively simple, but it does require precision. Here’s what you need to get the task done safely and correctly:

Calculator: Have a calculator on hand to make sure you add up measurements correctly. A basic calculator or your smartphone’s calculator app will work.
Camera: To take photos of specific corners, roof sections, or the existing gutters to use as a reference when selecting materials or explaining your project to contractors.
Chalk: If your tape measure isn’t long enough to measure the entire gutter run at once, you’ll need chalk to mark where one measurement ends and the next begins.
Gloves and safety goggles: Gloves protect your hands from sharp edges or debris. Choose a pair with a good grip, especially if handling tools beyond a tape measure and level.
Ladder: Rent or buy a stable ladder tall enough to reach your gutters easily. If using an extendable ladder, invest in a stabilizer or standoff attachment.
Level: Your roof’s pitch can impact the size and type of gutters that are required. You’ll need a 12-inch level to measure pitch.
Notepad and pen: Have a pen and paper handy or use a note-taking app on your phone to record measurements.
String or twine: Gutters should slope downward slightly (about 1/4 inch per 10 feet) so that water flows freely toward the downspouts. If you’re starting from scratch or need to make an adjustment, use string or twine to mark the desired slope along the fascia board.
Tape measure: Opt for a sturdy, retractable measuring tape that spans at least 25 feet. Ideally, it should match or slightly exceed the length and width of your roof’s largest plane.

Pro tip: It’s helpful to have a partner when measuring gutters. Having someone to steady your ladder, keep the tape measure in place, and write down measurements will make the job much easier.

Step-by-Step Guide to Measuring Gutters

You need to get accurate measurements before repairing old gutters or installing new ones. Follow our step-by-step instructions to learn what to do.

Measuring Existing Gutters for Repair or Replacement

If you’re doing a simple repair or replacing gutters with an identical set, you only need to measure your existing gutters:

Measure the length: For a full gutter replacement, measure and record the entire length of your existing gutters. For repair, measure only the damaged sections.
Measure the width: Measure the distance from the side that sits flush against your home’s fascia—the board along the side of your roof’s overhang—to the edge that extends past the roofline. Residential gutters often come in 5- or 6-inch widths, but yours may be a different size.
Measure the downspouts: If your gutters have downspouts, record the height of each one. Account for the angled extension at the bottom.
Count the corners, end caps, and elbow pieces: Note how many end caps are right ends and how many are left ends. Count the corner pieces and the number of elbow pieces required for your downspouts.

Measuring for New Gutter Installation

Measuring for a completely new gutter installation is more involved than measuring for replacement. You’ll need to determine the volume of water your gutters can handle and the linear feet needed. This means figuring out the area of your roof, the roof pitch, and the average rainfall in your area.

Measure the roofline: Measure the length of each roof section that will have gutters attached to determine the total length of your gutters.
Calculate the drainage area: Measure the length and width of each plane of your roof, just as you would when measuring for shingles. Multiply those numbers to calculate the square footage of each section separately, then add all those areas together. The total square footage is the drainage area.
Determine roof pitch: Use a level to measure your roof’s vertical rise over a 12-inch horizontal run. This tells you the roof’s pitch, which you can use to determine the roof-pitch factor or multiplier:
- 4:12 or 5:12 = 1.05
- 6:12 to 8:12 = 1.1
- 9:12 to 11:12 = 1.2
- 12:12 or higher = 1.3
Determine rainfall intensity: Look up the maximum rainfall intensity for your area on the NOAA website. Enter your location, select “precipitation intensity” for the data type, and scroll down to the table. Use the bolded number in the fourth column of the first row (5-minute duration, 10-year recurrence interval).
Calculate the adjusted square footage: Multiply your roof’s square footage by the roof pitch factor and rainfall intensity. The product of these three numbers is the adjusted square footage, which you use to determine how wide your gutters should be.
Measure for downspouts: Plan to have one downspout for every 25–30 linear feet of gutters. Measure the distance from your roofline to the ground, plus at least 4 feet for a gutter extension. Multiply this by the number of downspouts needed.
Count corners, end caps, and elbows: Determine how many corner pieces, end caps, and downspout elbows you need for the gutter system.

Safety Considerations When Measuring Gutters

When measuring gutters, practice ladder safety and wear appropriate protective gear such as work gloves, safety goggles, and nonslip shoes. Position your ladder on a stable, flat surface and have someone nearby to steady it. Avoid overreaching and stay well away from electrical lines.

Wet roofs and ladders are dangerous, so plan your project for a dry day and postpone if there’s unexpected rain or wind. Stay hydrated and take frequent breaks on hot days.

How To Choose the Right Gutters

You’ll need to consider more than size to choose gutters for your home. Here are some other factors to keep in mind:

Aesthetics: Choose a style and color that complements your home. K-style gutters are popular for modern homes, while half-rounds add charm to older, traditional designs.
Budget: While cheaper options can be tempting, investing in durable gutters can save money over time through fewer repairs. Look for options that balance material quality, maintenance needs, and warranty coverage for peace of mind.
Quality: Research the performance and durability of several styles, materials, and brands to choose the best gutters for your home.

Think about investing in upgrades that will improve your gutters’ performance and longevity. Seamless gutters cost more than sectional gutters but last longer, and installing gutter guards can help prevent clogging. The best gutter guards, including LeafFilter and Leafguard, come with lifetime warranties.

FAQ About Measuring Gutters

Are gutters measured in linear feet?

Gutters are usually measured and sold in linear feet. But gutters also come in different styles and sizes, or widths, measured in inches.

How do I know what size my gutters are?

You can figure out the size of your gutters by measuring them yourself. Follow the instructions in this article to measure your gutters. When you’re buying new gutters, you’ll need to know the length in linear feet and the width in inches.

What is the most popular gutter size?

The most popular gutter size is 5-inch K-style gutters. They offer a good balance of water capacity and affordability for most houses. However, 6-inch gutters may be a better choice for larger roofs or areas with heavy rainfall.

How do I tell if I have 5- or 6-inch gutters?

You can tell if you have 5- or 6-inch gutters by measuring the width of the gutter opening at the top. If the opening is about 5 inches, you have 5-inch gutters. If it’s closer to 6 inches, you have 6-inch gutters.

What is the cost difference between 5-inch and 6-inch gutters?

The cost difference between 5-inch and 6-inch gutters depends on the material and brand. You can expect 6-inch gutters to cost about $1 more per linear foot than 5-inch gutters.

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