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Garage Size Calculator
Use this free garage size calculator to work out how big a garage you need before you build or buy. Enter your cars, trucks, and motorcycles, add storage or a workshop, and the calculator works out the width and depth you need, recommends the nearest standard garage size, and tells you what garage doors fit it.
A workshop bay holds a workbench, tools, and room to work. Some storage covers shelves, bikes, and lawn gear along one wall.
| Amount | Value |
|---|---|
| Vehicle bays | 2 cars |
| Minimum width needed | 28 ft |
| Minimum depth needed | 20 ft |
| Minimum area | 560 sq ft |
| Recommended size | 30 ft × 22 ft |
| Recommended area | 660 sq ft |
| Garage doors | Two 9 ft single doors |
How it works
A garage size is decided by width first, because width is what makes a garage feel roomy or cramped. Each car bay needs about 10 feet of width: the car itself is around 6 feet wide with its mirrors, and the remaining 4 feet give you room to open the doors and walk around it. A truck bay needs 11 feet, because trucks are wider and taller, and a motorcycle needs about 4 feet parked at an angle along a wall. Storage and workspace add width too: 4 feet for shelves and lawn gear along one wall, or 8 feet for a proper workshop with a bench and room to work.
Depth is simpler. A standard car is about 15 to 16 feet long, so 20 feet of depth leaves room to walk behind it, store a few things, and close the door without worry. A full-size pickup runs 19 to 20 feet long, so any truck in the plan pushes the depth to 22 feet. Multiply the minimum width by the minimum depth to get the minimum area, but do not build the minimum: garages are built in standard sizes, and the calculator rounds up to the next standard size, because the cost difference between a tight garage and a comfortable one is small compared with the cost of wishing you had built bigger.
Minimum depth = 22 ft if any truck, otherwise 20 ft
Minimum area = minimum width × minimum depth
Recommended size = smallest standard size at least as wide and deep as the minimum
Standard sizes: 12×20, 12×22, 20×20, 20×22, 24×22, 30×22, 36×22, 36×24 ft
The standard sizes the calculator rounds up to are the ones builders actually use. A 1-car garage is 12 by 20 or 12 by 22 feet. A 2-car garage is 20 by 20 or 20 by 22 feet, or 24 feet wide for extra comfort. A 3-car garage is 30 by 22 feet, and a 4-car garage is 36 by 22 or 36 by 24 feet. The recommended size is the smallest standard size that covers your minimum width and depth, so a 28 foot minimum width with a 20 foot minimum depth rounds up to a 30 by 22 foot garage, the standard 3-car size.
Doors follow from the bays. A single-car door is 8 or 9 feet wide, and 9 feet is the better choice, because an 8 foot door leaves little room for mirrors on a wide car. A double door for two cars is 16 feet wide. Two single doors are usually the better choice for a 2-car garage: you can open one side without opening the whole garage, and a broken opener only takes out one bay. A 3-car garage usually has one double door plus one single door, or three single doors.
Before you settle on a size, think about what else will live in the garage. Bicycles, a mower, skis, and holiday boxes all need wall space, and they creep into the car bays if there is nowhere else for them. If the third bay would mostly hold boxes, a 2-car garage plus a garden shed is usually cheaper and more useful than a 3-car garage.
Worked example
You have 2 cars and want a workshop in the garage.
Step 1: Minimum width — 2 cars × 10 ft = 20 ft, plus 8 ft for the workshop = 28 ft.
Step 2: Minimum depth — no truck, so 20 ft.
Step 3: Minimum area — 28 × 20 = 560 sq ft.
Step 4: Round up to a standard size — the smallest standard size at least 28 ft wide and 20 ft deep is 30 ft × 22 ft.
Step 5: Recommended area — 30 × 22 = 660 sq ft, with two 9 ft single doors.
The result is a recommended garage of 30 ft × 22 ft, or 660 sq ft, which is a standard 3-car size with room for 2 cars and a workshop.
FAQ
What is a standard 2-car garage size?
A standard 2-car garage is 20 feet wide by 20 to 22 feet deep, which is 400 to 440 square feet. That gives each car about 10 feet of width, enough to open the doors without hitting the wall or the next car, and about 20 feet of depth for the car plus a walkway at the back. A 24 foot wide garage is more comfortable if you have large vehicles or want room for a workbench along one wall.
How wide should a garage door be?
A single-car door is usually 8 or 9 feet wide, and a double door for two cars is usually 16 feet wide. A 9 foot door is the better choice for a single bay, because an 8 foot door leaves little room for mirrors on a wide car or truck. For a 2-car garage, two 9 foot doors give more flexibility than one 16 foot door: you can open one side without opening the whole garage, and a broken opener only takes out one bay.
How much room do I need to open car doors in a garage?
Allow about 10 feet of width per car bay, which leaves roughly 2 to 3 feet between the car and the wall or the next car once the car itself, at about 6 feet wide with mirrors, is parked. A garage that is only 18 feet wide for two cars feels cramped, because the doors hit the wall and you have to squeeze out sideways. If you carry children or car seats, 11 feet per bay is worth the extra concrete.
How deep should a garage be for a truck?
A full-size pickup is about 19 to 20 feet long, so a garage needs to be at least 22 feet deep to hold it with room to walk behind it and close the door. A standard car is about 15 to 16 feet long and fits in a 20 foot deep garage with space to spare. This calculator uses 22 feet of depth whenever you add a truck, and 20 feet for cars only.
Is a 3-car garage worth it?
A 3-car garage, usually 30 to 36 feet wide by 22 feet deep, is worth it if you have three vehicles, or two vehicles plus a workshop, gym, or serious storage. It costs more to build, heat, and pave a driveway for, but it adds resale value and keeps a third vehicle out of the weather. If the third bay would mostly hold boxes, a 2-car garage with a storage shed is usually cheaper and more useful.