Garage Dimensions: 1-Car & 2-Car Sizes, Width and Square Feet

What size is a standard garage?

There is no single U.S. garage size used by every builder or required nationwide. A planning table in Transportation Research Board Circular E-C019 lists these recommended clear interior dimensions for residential garages:

Garage layout	Recommended minimum	Desirable planning size	Approx. interior area
One car	11 × 21 ft	13 × 24 ft	231–312 sq ft
Two cars, side by side	20 × 21 ft	22 × 24 ft	420–528 sq ft

These dimensions multiply the report’s inside width by its inside length. “Minimum” and “desirable” are the report’s planning recommendations, not universal legal requirements or a statistical average. Local rules and the vehicles, doors, storage, and clearances you need can change the right size.

One-car and two-car garage dimensions

The TRB table recommends an interior width of 11 feet minimum or 13 feet desirable for one car, and 20 feet minimum or 22 feet desirable for two cars. Its recommended inside length is 21 feet minimum or 24 feet desirable.

Measurement	One-car recommendation	Two-car recommendation
Inside width, minimum	11 ft (3.35 m)	20 ft (6.10 m)
Inside width, desirable	13 ft (3.96 m)	22 ft (6.71 m)
Inside length, minimum	21 ft (6.40 m)	21 ft (6.40 m)
Inside length, desirable	24 ft (7.32 m)	24 ft (7.32 m)
Garage door width listed by TRB	9 ft	18 ft for two cars

The same report notes that some one-car doors are 8 feet wide and many two-car garages have a 16-foot door. Door opening, wall width, and clear interior space are different measurements; measure the unobstructed space inside the finished walls.

How many square feet is a garage?

Multiply the inside width by the inside length to estimate the rectangular floor area:

One-car minimum recommendation: 11 × 21 = 231 square feet.
One-car desirable size: 13 × 24 = 312 square feet.
Two-car minimum recommendation: 20 × 21 = 420 square feet.
Two-car desirable size: 22 × 24 = 528 square feet.

These are floor-area calculations from the dimensions above. They do not add wall thickness, storage shelves, stairs, utility equipment, or extra room to open doors. The two-car examples are side-by-side layouts; a tandem garage has a different shape and is not covered here.

How to choose a usable garage size

Check the specific vehicle and the clear interior, rather than relying only on “one-car” or “two-car” labels. Measure the vehicle’s length and width, including mirrors where relevant, then allow room for opening doors, walking around it, and any storage or equipment along the walls.

The TRB report explains that its desirable dimensions allow more space for cabinets, a workbench, equipment, and storage. A larger SUV or truck, shelves, water heaters, or other obstructions can reduce usable parking space. Exterior dimensions and advertised floor area may not equal the unobstructed inside dimensions.

Building and zoning rules vary by location. These cited figures are planning references, not a substitute for checking local requirements or the dimensions of the actual garage.

Frequently asked questions

What is a typical one-car garage size?

The cited TRB table recommends 11 × 21 feet inside as a minimum planning dimension and 13 × 24 feet as a desirable size. These are source-specific recommendations, not a national statistical average.

How big should a two-car garage be?

The same table lists 20 × 21 feet inside as a minimum recommendation and 22 × 24 feet as desirable. Measure both vehicles and allow for doors, walking space, and storage before choosing a footprint.

How many square feet is a two-car garage?

The cited examples calculate to 420 square feet at 20 × 21 feet and 528 square feet at 22 × 24 feet.

Is there a universal standard garage size?

No. Garage dimensions vary by location and use. Check local rules and the clear interior measurements of the specific space.

Does this page give a standard garage height?

No. The referenced table does not set a garage height; door and ceiling heights need to be checked against the vehicle and local requirements.