Home Gutters How to Measure Gutters for Your Home

How to Measure Gutters for Your Home

If you want to learn how to measure gutters for your home, chances are the ones you have aren’t working well, or you’re installing gutters on a new home.  

Gutters perform best when sized correctly for your roof design and size. Their ultimate function is to remove water from your roof and drain it away from your home to prevent water damage. 

If you want to learn how to measure gutter size, we’ll show you how to do it like the professionals so your gutters work efficiently. We’ll also help you learn more about gutter sizing, as understanding gutter dimensions can help you appreciate how gutters work and can help you prevent future problems.

What Equipment Will I Need?

Measuring gutters for your home isn’t complicated if you’re a veteran DIYer. But, precision and safety are essential when undertaking the task.

Accurate measurements are necessary for correct sizing, and attention to safety is paramount to keep you and those around you safe. Falls are the second-highest cause of death and the leading cause of non-fatal injuries in the home environment. 

You’ll need a few tools plus appropriate safety gear. Remember, ladders can be dangerous with or without adequate experience in using them. Always follow common sense safety rules when using your tools, ladders, and stabilizers.

Here’s a partial list of the tools and personal protective equipment (PPE) you may need to measure gutters for your home accurately and safely:

unchecked PPE, including soft soles, closed-toe shoes or boots with a good grip, glasses to shield your eyes from the sun, gloves, and a safety harness if you plan to go on the roof (if your roof is steep, please enlist the help of a gutter specialist)

unchecked A sturdy, stable ladder that extends at least 4’ to 6’ past the gutters

unchecked Measuring tape

unchecked A pencil and paper or smartphone to record your measurements (Some smartphone apps allow you to use your phone’s camera to measure)

unchecked Another person standing by in case of an emergency

Measuring Gutter Length

Homeowners often wonder, “How are gutters measured?” Gutter dimensions will vary from one design to another, and knowing how to measure gutter size correctly is critical to their performance. 

Gutter dimensions refer to the width and length of the gutter section and indicate how much water the gutter will effectively control.

If you already have gutters on your home and want to replace them, you can accurately measure them to determine what you need. 

If your roof is safe to walk on and you have the experience and safety gear to climb onto the top safely, measuring from the roof is the most accurate method. However, you can also use laser tools to measure your gutters from the safety of the ground if you understand the process.

Gutters usually extend one inch beyond the edge of the shingles from side to side. You’ll need to add two inches to your measurement if you use the edge of the shingles to measure from. This allows the gutters to be sloped appropriately without becoming too short.

If your measuring tape is too short to complete the measurement in one pass, lay a pencil on the roof and use it as a demarcation point. 

For example, if the roof is 48’ long, but your tape is only 25’, just extend it as far as it goes and use the pencil to mark the spot. Then, begin again from that point and finish the measurement.

If your roof is longer than 50’, investing in a longer measuring tape is best to avoid accumulating errors each time you move the tape.

Determining Ideal Gutter Width

Standard residential gutters are 5” wide at the top, where the runoff falls into the gutter. Most residential gutters are K-style, but other versions are available. Half-round (aka trough style) gutters are common, as are box style. 

Commercial gutter sizes generally begin at 6” wide versions, but 7” and 8” sizes are also available.

Generally, the larger the gutter opening and downspout opening, the better to avoid clogs and overflows. 

However, builders aim for a balance of performance, cost, and curb appeal when measuring gutters for your home. Oversized gutters can become an eyesore if they do not match the home’s design and add unnecessary weight.  

Generally, if your total roof area is 2,500 square feet or less, the standard 5” gutter size is adequate. However, if your roof is subject to debris that constantly clogs your gutter system, upgrading to a 6” gutter (and 3” x 4” downspouts) is a more appropriate solution.

Calculating Total Linear Feet

Many gutters are priced by the linear foot. Roofers use different ways to calculate total linear feet for gutters. 

Some use a simple calculation of taking the square footage of your home and dividing it by 10. So, with a 2,000-square-foot house divided by 10, you’d need 200 linear feet of gutters. 

Others prefer more accurate calculations when determining how many linear feet are needed for gutters. In this case, they would use your home’s footprint measurement or its outside width x depth. 

So, if your home’s outside width is 30 feet and its depth is 40 feet, its footprint would be 1,200 square feet. Then, you would divide that by 10 to end up with 200 linear feet of gutters.

Gutters are available in sections (usually 10 feet long) or seamless, continuous gutters that you can assemble yourself. Sectional gutters will have a greater propensity to leak due to the multiple joints required.

Seamless gutters usually require professional installation as they are custom-made for your home onsite using a truck-mounted forming machine. A professional gutter company typically has a few technicians at a job site when installing seamless gutters because the lengths can be very long and awkward to handle.

Accurate measuring is essential because custom gutters are typically non-returnable. However, a seamless guttering company will double-check your measurements before forming the new gutters to fit.

Common Measurement Mistakes to Avoid

Here are a few common mistakes made by first-timers when measuring their home for new gutters and how to avoid them:

Incorrect Gutter Slope 

All gutters will have a slope to some degree and drain into a scupper, drain, or downspout. Guttering is generally sloped at a ratio of ¼” to ½” per 10 feet of length, but each gutter type may have its own installation requirements. The key is to follow manufacturer guidelines for each kind.

Neglecting Drip Edge Flashing

Drip edge flashing is a strip of aluminum or vinyl formed into a 90-degree angle along its entire length. One side of the drip edge flashing slides under the starter shingles and over the back of the gutter. This prevents water from contacting the roof sheathing, which can cause rot, mold, and insect infestations.

Incorrect Fasteners

Gutters can be installed using gutter spikes, gutter screws, hidden hangers, and metal straps. Be sure to choose the correct fastener for the gutter type you decide to improve performance and avoid damaging the gutters when filled with water.

Hiring a Professional

There are benefits to hiring a professional gutter company to measure and install your new gutters, including:

  • Expert measuring and advice
  • Expert installation
  • Speed of completion
  • Expert safety precautions
  • Warranty
  • Maintenance support
  • Documentation (for future owners of your home)

Most homeowners consider professional installation to be a wise investment in their homes. A new, professionally installed gutter system increases your home’s value, keeps you off a ladder, and offers you a professional to call on for emergency repairs.

Contact our gutter experts, and we’ll assess your home and make the correct recommendations regarding the best gutter type, size, and slop for your home. 

Leave Your Gutter Project With Us, and We’ll Leave You With Peace of Mind

If you decide to DIY your home’s gutters, follow manufacturer guidelines and use the correct tools and safety procedures. Accuracy and precision are crucial, but always remember safety should come first.

Learning how to measure gutter size is the easy part. The actual installation of your gutters is a much more physically tasking job. That’s why many homeowners rely on All Star Home for their gutter measuring and installation.

With us, you get quality, industry experience and knowledge, support, and expert installation you can depend on. Contact us for a free estimate today!


How do I know what size my gutter is?

Learning how to measure for gutters begins with understanding how gutters work. Gutters are categorized by the width of the gutter at its top opening, not their overall length. Each gutter type will hold a finite amount of water per linear foot, so we can use the information to calculate which type we need.

To measure gutter width, use a measuring tape or ruler and measure from the back of the gutter to the front (the side facing out). Usually, K-style gutters will be either 5”, 6”, or 7” wide.

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

Most homes have 5” wide, K-style gutters. You can measure the opening as described previously to be sure, or you can compare the size of the gutter to a one-dollar bill. If the gutter is about as wide as a dollar bill is long, you have 6” gutters. If the bill folds over the edge, you have 5” gutters.

What is the rule of thumb for gutter size?

Understanding how to size a gutter system for your roof will help you avoid costly mistakes. Generally, 5” gutters are appropriate for up to 2,000 to 2,500 square feet of roof area. However, the pitch of your roof may require a wider gutter.

If the roof is very steep, the velocity of the water may cause the runoff to overshoot a more narrow gutter, missing the gutter entirely. Conversely, if your roof pitch is very shallow (less than 3:12), ice dams and other destructive occurrences can render your gutters useless.