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How to Measure the Size Garage Door

How to Measure the Size Garage Door

At Mehr’s Garage Doors, we know your garage door is more than just a valuable part of your home. It’s also a statement piece that makes your home look better, keeps it safer, and uses less energy. If you want to put in a new garage door or replace an old one, you must ensure you have the correct measurements.

You might think measuring your garage door is difficult, but with our help, you’ll have the knowledge and tools to do it right the first time. Accurate measurements help ensure a perfect fit, ease installation stress and save you time and money in the long run. In this in-depth guide, we’ll show you how to measure your garage door side by side, point out the usual sizes and constraints, and advise on how to get the best fit.

How to Measure the Opening of a Garage Door

Make sure you have the right tools for the job before we get into the details of measuring:

25-foot tape measure: With a long tape measure, you can get accurate numbers without stopping and starting.

Pen and paper: You should write down your measurements as you go.

Step ladder: A ladder will come in handy to measure the height of your garage door opening.

Level: Use a level to see if the floor of your garage is level and free of any bumps or slopes.

Now that you have these things, you can start measuring the opening for your garage door.

Measuring the Width of Your Garage Door

One of the most important measurements you’ll need to take is the width of your garage door opening. How to do it:

Start by measuring from the inside of one jamb to the other. This is how far the left and right sides of the final opening are from each other.

With your 25-foot tape measure, you can get exact readings without problems.

Ensure you measure at the opening’s most significant point to account for flaws.

Write down the measurement to the exact inch.

Tip: If your garage has two doors, measure each opening separately because they may be slightly different sizes.

How to Find Out How High Your Garage Door Opening Is

Measuring the height of your garage door opening comes next. How to do it right:

At three different points on the header, measure from the floor to the bottom. These are the left, center, and right.

The floor is this far away from the top of the final opening.

Check if the floor is level and free of bumps or slopes.

Make a note of the most significant measurement to make sure the new garage door fits right.

A helpful hint is that if the three measurements show significant differences in height, your garage floor may need to be level. In this situation, it’s best to talk to a professional to figure out what to do.

How Much Headroom and Side Room Does Your Garage Door Need

Headroom and side room measurements tell you what kind of track layout and spring system your garage door needs. How to measure them:


Measure the space between the top of the garage door opening and the ceiling (or the lowest object blocking the view, like light fixtures or pipes). This is called headroom.

The type of track setup your garage door will need will depend on this measurement.

Standard systems require 12 inches of headroom, and openers usually need an extra 3 inches.

Side Room:

Find out how much room there is on both sides of the garage door opening.

This space must be at least 3-3/4 inches on all sides for regular torsion springs and extension springs.

If you’re putting in a garage with two doors, the center post between them will need twice as much side space.

Tip: Special kits and setups can be used with limited headroom or side room. Talk to the professionals at Mehr’s Garage Doors to get the best answer for your needs.

How to Find Out How Deep or How Much Backroom Your Garage Has

This is the area between your garage door’s opening and your garage’s back wall. It’s also called “backroom.” This is how to measure it:

Start at the garage door opening and measure straight back to the back wall of the garage (or the first thing that gets in the way, like a desk or shelves).

The least amount of depth needed is 18 inches more than the height of your garage door.

If you want to install a robotic garage door opener, you’ll need an extra 4 feet of depth.

Tip: If your garage roof is sloped or uneven, measure more than once to ensure enough space for your new garage door.

Standard Garage Door Sizes and Considerations

Now that you know how to measure your side door opening, let’s look at standard garage door sizes and factors.

Single garage doors:

The widest points are 8, 9, or 10 feet.

Seven feet tall is the norm.

Double garage doors:

The widest points are 12, 14, 16, or 18 feet.

Seven feet tall is the norm.

Custom Garage Doors:

Available in almost any size to fit different rooms and building styles

Ideal for garage door openings that aren’t standard or old houses

Consider the following when selecting your garage door size:

The size of your cars

How much room do you need to store things

The style of building your home

Rules and rules for building in your area

At Mehr’s Garage Doors, we offer many garage door types and sizes to fit any home and budget. We’re here to help you find the best option for your needs.

How to Make Sure Your Garage Door Measurements Are Correct

The key to a sound garage door installation is getting the measurements right. To help you do it right, here are some tips:

Measure twice: Check your measurements twice before you place your order to avoid mistakes that will cost you a lot of money.

Use a robust and good-quality tape measure: If it is weak or pulled out, it can give you wrong measurements.

Measure to the nearest inch: Most garage door sizes are in inches, so write down your measurements correctly.

Account for any obstructions: Write down the names of pipes, wires, or other things that could prevent you from installing your garage door.

Check for level and plumb: Check that the floor and walls of your garage are level and straight with level.

If you remember these tips and take your time measuring, you should be able to find the right garage door for your home.

When you should get help from a professional to measure your garage door

Even though measuring your garage door opening is pretty easy, there are times when you should get help from a professional:

Unusual or non-standard garage door openings: A professional can help you determine the best way to fix your door opening if it is an odd shape or size.

Uneven or sloped garage floors: If your garage floor has big bumps, they can affect how well and safely your garage door works. A professional can examine the problem and tell you what to do next.

Historic homes or custom designs: A professional can ensure that your measurements and specs are correct if you have an old house or want a custom garage door design.

Mehr’s Garage Doors employees are here to help you with your garage door needs. We can help you with everything, from measuring and choosing the right door to installing it and keeping it in good shape.


Congratulations! Now you know how to correctly measure your garage door opening and have the right tools. What will happen next? After measuring, do these things:

Choose your garage door style and material: Use your measurements to browse our garage doors and find the right style and material for your home.

Request a quote: Please give our team your measurements and the garage door details you want for a total price.

Schedule your installation: After you agree to the price, we’ll schedule a time for our skilled technicians to install your garage door.

Enjoy your new garage door: Take it easy and enjoy how it makes your home look better, keeps you safe, and works better.

Mehr’s Garage Doors is dedicated to providing our valued customers in St. George and nearby places with the best service and highest-quality products. For all of your garage door needs, we’re the best. We have over 40 years of experience, a great name, and custom solutions for every job.

There is no such thing as a one-size-fits-all garage door. Mehr’s Garage Doors has professionals who can help you with every step, from getting the correct measurements to installing the door perfectly. Contact us immediately to set up your meeting and make your home better with a beautiful, well-functioning garage door.