Garage Dimensions Planner
Pick the vehicles you park and how much room you want around them. The planner draws the floor to scale and gives the inside dimensions, the garage doors and the heat the space needs.
What you park
Inside dimensions
25 × 23 ft, 575 sq ft
That is roomier than most 2-car garages, which go up to about 24 × 24 ft. With 2 ft of room instead of 3 it would be 22 × 21 ft.
- Garage doors
- 2 singles, 10 × 7 ft
- Ceiling
- 8 ft
Standard garage sizes
| Garage | Common size | Range | Doors |
|---|---|---|---|
| 1-car | 12 × 20 ft, 240 sq ft | 10 × 18 to 16 × 24 ft | One 9 × 7 ft |
| 2-car | 20 × 20 ft, 400 sq ft | 20 × 20 to 24 × 24 ft | One 16 × 7 ft or two 9 × 7 ft |
| 3-car | 30 × 20 ft, 600 sq ft | 30 × 20 to 36 × 24 ft | A double and a single, or three singles |
These are inside dimensions. The 1-car and 3-car figures are HomeGuide's and the 2-car range is Reolink's; builders round to whole or even feet. The smallest sizes only work for smaller cars with little room to open the doors.
How the planner sizes the floor
It adds each vehicle's width plus 1.5 ft for the mirrors, then the room you picked beside every wall and between the cars: 2 ft is tight, 3 ft lets the doors open fully. The depth is the longest vehicle plus that room in front and behind, and 4 ft more for a workbench. Both are rounded up to the next foot.
Vehicle sizes are HomeGuide's averages, from a Honda Civic at 15 ft long to a Ram 2500 at 19.5 ft. Measure your own vehicles if they are close to the limit, and check local building codes before you build.
Garage size and heating
A bigger floor and a taller ceiling mean more air to heat and more wall and door to lose heat through. Going from 20 × 20 to 24 × 24 ft adds 44% more floor area. Insulating the door and ceiling saves more heat than shrinking the plan; the garage insulation cost calculator prices it. For heater sizes by garage, see the 2-car garage heater size guide and the garage heater BTU chart.
Questions people ask
What are standard garage dimensions?
A standard 1-car garage is about 12 × 20 ft (240 sq ft), a 2-car garage about 20 × 20 ft (400 sq ft), and a 3-car garage about 30 × 20 ft (600 sq ft). Many newer 2-car garages are 22 × 22 or 24 × 24 ft, and 3-car garages run up to about 36 × 24 ft.
What is the minimum size for a 2-car garage?
About 20 × 20 ft. That fits two mid-size sedans with only about 2 ft around each one: our planner gives 22 × 20 ft for that. With 3 ft around each car it grows to 25 × 22 ft, which is why 24 × 24 is a popular size.
How big is a 1-car garage?
The common size is 12 × 20 ft. A mid-size sedan fits in 12 × 20 ft with 2 ft of room around it, or 14 × 22 ft with 3 ft. A full-size pickup like the F-150 needs about 15 × 24 ft with 3 ft of room.
What size garage door do I need?
A standard single door is 9 ft wide and 7 ft tall, and a standard double is 16 × 7 ft. For a full-size SUV or pickup, a 10 ft single gives more room on each side, and a lifted truck or roof rack needs an 8 ft tall door.
How tall is a garage ceiling?
Usually 8 ft. A 9 ft ceiling suits lifted trucks and overhead storage racks, and 10 ft or more is for a car lift. A taller ceiling also adds air to heat, so the heater gets a little bigger.
What size heater does my garage need?
It depends on the size, the insulation and how cold it gets. Two cars in 25 × 22 ft with some insulation need about 23,500 BTU/hr to stay at 60°F on a 20°F night. The planner shows the number for your layout and links to the full calculation.
Sources
Sources last checked November 8, 2026.
- HomeGuide, How big is a one-car garage? (updated May 3, 2026) · vehicle sizes, 3 ft clearance, mirrors, door sizes, 1-, 2- and 3-car sizes
- Reolink, Standard garage size (Sep 13, 2024) · 2- and 3-car size ranges, 9 ft ceiling for tall vehicles
- Sheds Unlimited, 2-car garage dimensions (undated) · 2 to 3 ft beside each car, 4 ft for a workbench