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How to Measure for a Garage Door

Garage Measurements Matter for a New Garage Door and Opener

Residential Garage Doors / April 12, 2021
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How to Measure for a Garage Door



When choosing a garage door, it is easy to get caught up in the styles and models and forget to consider the garage door and opener clearance requirements.

It’s essential to choose the type and model garage door opener that matches your garage door’s specifications, and that fits your garage! All three must be in unison. It is important to measure for a garage door and opener. Without this, you might have an opener that won’t work or a garage door that won’t fit.

Garage Measurements. Do they really matter?

Yes! When purchasing a door or garage door opener from us, we do all the work for you.

For many, its convenient to be able to get a rough idea of your garage dimensions, even before a professional is called in.

If you feel like every inch counts to try to get a vehicle or specific equipment in the garage, consult Overhead Door Company of Huntsville™. We are door professionals, and it’s our specialty to share all options available to you as a garage door customer.

This article was written for “General Guideline” purposes. There are other options for your garage door and garage door operator installations. 


Will your garage door opener fit the clearance in your garage?

If you aren’t sure whether the garage door opener you like will meet the minimum clearance for your garage, you need to take some measurements.  The measuring process is simple and should only take about 20 minutes of your time. With this information, you can talk to one of the experts at Overhead Door Company of Huntsville™  to get the guidance you need in choosing your new opener and pricing.

The most common garage door sizes are 8×7, 9×7 and 16×7. Never assume that a door is a common size – measure all doors yourself.

What happens when the door opening is a little smaller or larger than a conventional-sized door? That’s where a good garage door installer comes in handy. We have the ability to determine what door or opener will work best for each garage simply because we have the experience of knowing exactly how much extra cheating room we have when it comes to odd openings.


Grab a measuring tape and let’s get started!

These measurements should always be double-checked by a garage door professional before any materials are purchased or installed. Because there are so many different styles of garage doors with random sizes and requirements, it’s always best to let a professional garage door installer help you find a door and opener that’s right for you and your particular garage.


Measure the height (up and down) of the door at the highest point to the lowest point. This is the space between the floor and the top of the finished opening. Look for irregularities, such as uneven floor. Be sure to take note of these irregularities.


Measure the width of the garage door (horizontal length, left to right). Use a tape measure to get the measurement from the inside of one reveal to the other side. Consider measuring from different points of the garage to make sure you are getting an accurate measurement.

For best results, the inside of the garage door opening should be framed with 2″ x 6″ wood. Look for general irregularities, such as jambs which are not square and unlevelled sides. Note those irregularities.


Measure the width of the areas beside the openings of the garage door. This is the space to the left and right side of the door. Are there any wires in the way? Be sure to note any barriers or obstructions that could get in the way of installation. These notes will make the installation easier. A minimum of 3.5″ to 4.5″ is required on either side of the door opening to mount the Safe-T-Beam® System.

Sideroom is measured from the door jamb to the nearest obstruction, usually being a wall.  In addition to the track brackets needing space to be fastened, the tube or shaft for the torsion springs also needs space. Up to 5″ is required on each side for installation of the vertical track. Side mounted openers have special side room requirements.

If this is a 2-door installation, center post should be a min. of 10″ wide.


How much headroom is required above a residential garage door?

The answer is that it varies, but in many cases, even owners with low garage ceilings can find an opener that will provide excellent function without taking up too much room.

There are many critical dimensions involved in having a garage door and opener installed. One of the most confusing and least understood is headroom. Simply put, headroom is the space between your ceiling and top of your garage door. Without proper spacing, a garage door just won’t work.

Most standard automatic openers require at least 12 inches of overhead clearance, some taking 18 inches. This includes about 12 inches for the door and torsion springs and three inches for the garage door opener. Some wood garage doors might require 18″ headroom. Carriage House-style doors generally require additional room. Always be sure to verify this measurement with your garage door installer before purchasing any garage doors or equipment.

Getting the headroom measurement correct will allow your garage door to move around the radius of the track without hitting the ceiling.

We often have someone report headroom measured solely at the area of the door, only to be surprised when we make a site inspection and inform them special tracking may be required or the desired garage door size will not work at all due to one or more of the obstructions.

When you measure, account for any obstructions that may be in the way of the ceiling. Lights, sprinklers, electrical outlets, air ducts, sound systems, storage or shelving, etc.

Typical Garage Headroom Clearance Requirements

Torsion Springs 

Besides getting the headroom right, there are a couple of things that you should keep in mind. One, it is a good idea to opt for torsion springs for your garage door. These will improve your door’s operations and increase safety. Two, the use of safety cables enhances the security of your garage door, and ultimately, the security of your house.

Those within the industry appreciate the safety of torsion springs. These devices attach to the opener and the garage door, creating tension that pulls the door up and down. You mount torsion springs on the bar that sits above the door.

Torsion springs require a slightly higher clearance in your garage than the alternative. It takes about 12 inches of clearance to install torsion springs due to the brackets that hold the torsions bar in place at either end. You’ll need this full 12 inches for the installation of standard torsion springs. That doesn’t sound like much space, but you’ll need all of it for proper spring installation.

Extension Springs 

Extension springs are considered the secondary option for garage door openers. Torsion springs generally stay in place more effectively, but extension springs take up less room in the garage because they attach to the upper tracks and snake down the side. The majority of normal garage doors fit with extension springs need at least  9 to 12 inches of headroom. Before you purchase your new garage door opener, make sure you ask about the dimensions on the one you want to buy.


Low Headroom Clearance Requirements

A double-track system may work best for certain homes with low garage ceilings. You can find double-track extension springs that measure as little as 5 inches, though some require the full 12 inches.

These have a top roller that runs down the higher horizontal track, with the other rollers rolling down the lower horizontal track.

Torsion Springs 

With this, torsion spring garage doors need at least 9.5 inches of headroom. While it is possible to have torsion springs in garage with only 5 inches of headroom, this will require the mounting of the torsion springs on the back of the horizontal tracks, which can be quite difficult.

Extension Springs

Extension spring garage doors need at least 4.5 inches of headroom.

Allowing headroom for proper track radius

  • Low Headroom Track (Minimum of 8” to 13”).
  • 12” Radius Track (13” to 16”)
  • 15” Radius Track (Minimum of 16”).
  • 32” radius, high lift, follow the pitch track.  Available upon request.  Please consult Overhead Door Company of Huntsville™  for specifications. 

Measure the Backroom

Also called the “depth”.

The backroom is a measurement for the header to the nearest obstruction behind the travel of the door while overhead.

Backroom is important as it ensures the door, opener and horizontal tracks will have enough space to be installed. This space holds the entire door when it’s opened as well as some of the hardware and electric operator. Additional backroom is often required for the door height extension so this measurement will be longer than the actual height of the rough door opening.

This is the distance from the garage door opening to the back wall of the garage. A minimum depth of the door’s height plus 18” is required for manually operated doors, whereas a garage door opener can require the door height plus an additional 3’ to 4’ (for standard 7’ or 8’ high doors, depending on model). Remember that electric motorheads are typically placed 9.5’ to 11.5’ (for standard 7’ or 8’ high doors) from the garage door, so ensure a 120VAC outlet is within 36″ of this location.

When measuring the depth, it’s also important to check for any obstructions such as attic access,  storage, and beams or rafters that may be hanging down in the way of the installation..

Highest Point of Travel

This distance is measured from the ceiling to the highest point of the leading edge of the garage door when being raised. Sectional doors require a minimum of 2.5” for installing of an electric opener.

Upgrade Your Garage Door or Opener With Us!

Are you ready to take the next step in upgrading your garage door opener? Now that you’ve learned the importance of precise measurements from our recent blog post, it’s time to explore the perfect options we have in store for you. Click the link below to discover the exceptional range of garage door openers offered by Overhead Door Company of Huntsville/North Alabama™. Don’t miss out on the opportunity to enhance the functionality and security of your garage. Take action now!

Explore Our Garage Door Opener Selection

Explore our Garage Door Collections 

Call Us to Today

Overhead Door Company 
of Huntsville/North Alabama™
9550 Madison Blvd. 
Huntsville, AL 35758

Please visit our Troubleshooting Guide for more information on this and other garage door tips and troubleshooting.