Finally, after going through all the pros and cons, you have decided to install a metal garage on your lot. But you are asking yourself, what size should I choose? And, we’ll admit, that is a reasonable question. That’s why we have compiled some essential factors that you may find helpful when selecting garage dimensions. You can take a glimpse of them below.

Factors That Plays Key Role In Deciding Detached Garage’ Size


Your budget and the size of your garage will go along with each other. Hence, they must be balanced to get the best-finished product. You can consider adding aesthetics for one car garage with a high budget. However, you can focus on quality materials and a professional installation team for a tight budget. Aesthetics can be added later on.

On the contrary, you can downsize the garage from three to two and add a removable sidewall for expansion in the future. Steel garages overall cost less despite their higher initial costA finished metal structure costs between $11 to $26 per sq. ft.

Average Permit Cost for Metal Garage

Metal Garage: $50 to $300 (for small projects)  $500 to $2,000 (for larger project)
Electrical: $40 to $500
Deck: $50 to $600
HAVC: $200 to $500

But what should be the right budget for a one car or a three car garage? Don’t worry. We will discuss that later in this blog. But first, let’s move on to another crucial factor.

Available Property Space

Measure the land where you want to install your new metal detached garage to see if there is sufficient space for the following:

  • Your garage construction
  • No obstruction
  • Installation crew can move easily (else you may have to pay extra if they carry raw materials from a longer distance.)
  • Proper drainage
  • Enough space between your steel garage and your main home, fence, or your neighbor’s property.

Your Parking Needs

This can be further subdivided into the following categories for a better understanding.

  • No. of vehicles you want to park
  • Types of vehicles your metal garage will shelter
  • Size and height of vehicle that you want to accommodate

What do you want to park in your garage? This is crucial to know as its answer will help decide garage dimensions. For calculating the height of your detached garage, consider the tallest vehicle you own and select 6 to 8 inches longer leg height.

Storage Space Needs

Do you want to have some storage space in your steel garage?

  • If not, you can just choose dimensions 7-8 inches larger than your car.
  • If yes, you must select a large size to accommodate your car and your stuff.

You can install vertical shelves, racks, cabinets, pegboards, or foldable desks for working. This will let you store small stuff and your cars, too.

Multi-Functional Needs

Determining whether you want your garage to be multi-functional would be best. For instance, if you want to use your metal garage as a workshop or office, you must add an insulator for temperature regulation, a concrete base, and a HAVC system. You can add height to your garage & then install a mezzanine floor that can be used as an office space.

You can add more space to your steel garage for DIY projects, car repair and maintenance, or other work. To save bucks, go with more length than width. It will give you similar square footage but will cost less.

Future Expansion

There is always a possibility of increasing your garage dimensions in the future. One of the advantages of installing a detached garage is that you can expand it later. But you must ask your metal dealer to provide removable supporting sidewalls. In the future, if you want to increase the length, you can:

  • Remove this supporting sidewall
  • Add more side panels to increase the length
  • Re-install support sidewall back

Metal Garage Dimensions Based on No. of Cars

With an assumption that you have a regular-size car, let’s have a look at the sizes and estimate the price for a metal detached garage.

One Car

People with limited space can choose a standard one car garage. The dimensions are:

Width: 12 ft.
Length: 22 ft.
Height: 8 ft.
Cost: $4,600+

To park a mini truck or RV, you can adjust height, width, and length according to your vehicle’s type. For parking a car with additional storage, you can expand the length of your metal garage.

Two Car

People can choose a two car garage with additional space to store items. The dimensions are:

Width: 20 to 24 ft.
Length: 22 to 26 ft.
Height: 8 to 12 ft.
Cost: $6,600+

Three Or More Car

For three cars, people can select the following dimensions:

Width: 24 to 30 ft.
Length: 36 to 40 ft.
Height: 9 to 12 ft.
Cost: $9,600+

To park an RV, you can increase the leg height. You can opt for vertical roofing style as they are easy to maintain, especially for larger steel structures.

Note: To get a perfect garage size, you can give the size and model of your vehicle to Steel Builder’s customer support. They will help you with the appropriate dimensions.

Other Factors That Will Help You in Determining Perfect Garage Size

  1. Door Size: The standard door size for one car metal garage is 8 ft. wide x 7 ft. tall, but for a two car garage, it can be 16 ft. wide x 7 ft. tall. It is best to select a garage door that looks aesthetic yet robust to provide ample security.
  1. Vents: Vent will maintain air circulation & remove humidity from the indoor air.
  1. Insulation: Insulation is a must if you want your garage to last long. It will help minimize condensation and moisture build-up. This will, in turn, reduce the chances of rusting.
  1. Gauge Steel: The industry standard is 14 gauge; however, for extreme weather-prone areas, you can opt for 12 gauge steel.
  1. Lighting: If you want to spend a few hours in your garage every weekend, you need proper lighting.
  1. Security: By installing smart cameras around your metal garage trim, you can monitor the security of your belongings.

Counting Them All

We can say that a finished steel garage will cost, on average, $19 per sq. ft. It can be more dependent upon customization. But you can get affordable metal garages at the lowest price during the sale season. With low upkeep and sturdy structural strength, it will last you the longest.

At any point, you can convert your steel garage into a living space, be it an office, guest house, or personal art studio. You can check in with your local building codes for any design rules or restrictions. Some areas may require installation of your garage 10 ft. or more from the property line or your main home. When you file for a permit before installation, you shall get more details from the local authority. Ensure that you choose the best quality material for long-lasting structure.