For most homeowners, a 30x40 metal building is the safest all-around pick. It gives you 1,200 sq. ft. for vehicles, tools, shelves, and a workbench without feeling cramped. For 1 car, start around 12x20. For 2 cars, look at 20x21 or 24x26. For RVs, tractors, farm storage, or a small business, start at 40x60. Then check height, door size, roof style, and local code before you order.

Metal building size chart

Building size	Square footage	Best fit	Common uses
12x20	240 sq. ft.	1 small car or basic storage	Sedan, mower, ATV, garden tools
18x21	378 sq. ft.	1 vehicle with side space	Truck, SUV, motorcycles, shelves
20x21	420 sq. ft.	2 compact vehicles	2 cars, small garage, carport
24x26	624 sq. ft.	2 vehicles with storage	Trucks, workbench, freezer, tools
24x36	864 sq. ft.	Deep 2-car garage or small shop	Vehicles, trailer, mower, hobby shop
30x31	930 sq. ft.	3-car storage	3 cars, boat, side-by-side, yard gear
30x40	1,200 sq. ft.	Home garage and shop combo	Vehicles, tools, work area, storage
40x40	1,600 sq. ft.	Large shop or farm storage	Tractors, equipment, trailers, supplies
40x60	2,400 sq. ft.	Big shop, RV, farm, business	RVs, tractors, inventory, work bays
50x80	4,000 sq. ft.	Commercial or agricultural use	Fleet parking, hay, materials, equipment
60x100	6,000 sq. ft.	Large business or farm operation	Warehousing, machinery, bulk storage

A metal building size guide should start with what you’re storing. Then you work backward into width, length, height, doors, roof style, and certification.

Floor space gets most of the attention. Height and doors cause more real-world mistakes.

Quick size guide by buyer and use case

Buyer or use case	Good starting size	Better long-term size	Notes
1 car	12x20	18x21	Add width for shelves, bikes, or a mower
2 cars	20x21	24x26	Go wider for trucks and door swing room
3 cars	30x31	30x40	30x40 gives better storage and shop space
Pickup truck owner	18x21	24x26	Check truck length with tailgate down
RV owner	18x36	24x41 or larger	Measure full RV height, including roof accessories
Workshop	24x36	30x40	Plan around tools, benches, and walking space
Farm equipment	40x40	40x60	Width matters for tractors and implements
Contractor storage	30x40	40x60	Good for tools, trailers, job materials
Small business	40x60	50x80	Think inventory, loading, and future bays
Commercial storage	50x80	60x100	Plan access, code, doors, and traffic flow

1-car storage

For 1 car, a 12x20 metal building gives you 240 sq. ft. That’s enough for many sedans and small SUVs.

Tight, though.

A better daily-use size is 18x21. You get 378 sq. ft., which gives you more room to open doors, walk around the vehicle, and store a mower or a few shelves along the side.

Size	Use it for
12x20	Small car, ATV, mower, basic storage
18x21	Car, SUV, motorcycles, side storage
20x21	1 larger vehicle with better working room

Measure the vehicle first. Then add at least 3 ft. on each side for doors and walking space.

For a truck, add more.

2-car storage

A 20x21 metal garage gives you 420 sq. ft. and can work for 2 compact cars.

For full-size trucks or SUVs, 24x26 is a smarter size. That gives you 624 sq. ft., which feels much better once you add shelves, trash cans, yard tools, or a small bench.

Size	Best use
20x21	2 compact cars
22x26	2 cars with better door clearance
24x26	2 trucks or SUVs with storage
24x36	2 vehicles plus deeper storage or shop space

Depth matters as much as width.

A crew cab truck can run 20 ft. to 22 ft. long. Add a hitch, grille guard, tool box, or trailer tongue, and a short garage gets annoying fast.

3-car storage

For 3 vehicles, start with 30x31. That gives you 930 sq. ft.

It works for cars, a side-by-side, a mower, or a small boat. For a more comfortable setup, go 30x40. That extra depth turns the building into real storage instead of a parking shell.

A 30x40 metal building is a strong size for homeowners who need vehicles, tools, and a work area. You can park 2 or 3 vehicles, run a workbench along the back, and still keep wall space for ladders, bikes, compressors, and bins.

Size	Layout idea
30x31	3 cars or 2 cars plus equipment
30x40	2 to 3 vehicles plus shop and storage
40x40	Wider bays, larger tools, better turning room

Door layout matters here.

You might choose 3 smaller roll-up doors, 2 wider doors, or 1 large opening depending on how you park and what you drive.

Workshop space

A metal workshop size depends on how you work.

A hobby shop can fit in 24x36. A serious home shop usually feels better at 30x40. Contractors, welders, woodworkers, and mechanics often end up happier with 40x60.

Here’s the field rule: leave open floor space. A shop packed wall to wall becomes a storage unit with outlets.

Size	Good for
24x36	Hobby shop, small tools, 1 workbench
30x40	Home workshop, vehicle bay, tool storage
40x40	Bigger tools, more open floor, equipment
40x60	Multi-bay shop, business use, farm repair

For a real shop, plan for:

Workbench depth, usually 2 ft. to 3 ft.
Tool chests, often 2 ft. deep
Walkways around vehicles
Compressor or welder space
Shelving along one or two walls
Lighting and outlet placement
Insulation if you’ll work in heat, cold, or noise

A 30x40 metal building gives you enough room to park, work, and store. That’s why it’s one of the most common choices for homeowners.

RV storage

RV owners need to start with height.

A building can have enough floor space and still be too short. Measure the full height of your RV, including AC units, vents, antennas, ladders, satellite domes, roof racks, and anything else bolted to the roof.

Then add clearance.

Don’t cut this close. A roof AC scraping a header is an expensive lesson.

RV type	Starting size	Better size
Small camper	12x26	18x31
Travel trailer	18x36	20x41
Fifth wheel	18x41	24x46
Class A motorhome	18x41	24x51
RV plus storage	24x41	30x50 or larger

Most RV owners should look at taller legs, wider doors, and a vertical roof.

For RV metal building size, check:

Total RV length
Total RV height with roof accessories
Slide-outs, if you plan to open them inside
Mirror width
Door height
Turning room outside the building
Clearance for ladders and rear racks

A 12-ft. wall height might work for some campers. Larger RVs may need 14 ft., 16 ft., or more, depending on the unit and door setup.

Measure twice. Order once.

Farm and landowner storage

Farm and landowner storage gets big fast.

A tractor is one thing. A tractor with a loader, bush hog, hay spear, pallet forks, spreader, sprayer, side-by-side, fuel tank, and feed storage is a different plan.

Start around 40x40 for larger landowner storage. Move to 40x60 when you need tractors, RVs, farm supplies, and room to move around.

A 40x60 metal building works well for larger shops, tractors, RVs, farm storage, and small business storage. At 2,400 sq. ft., it gives you real working space.

Size	Common uses
24x36	Mowers, ATV, small tractor, tools
30x40	Compact tractor, implements, shop space
40x40	Tractor, trailer, supplies, repair area
40x60	Larger equipment, RV, feed, farm storage
50x80	Multiple machines, hay, bulk materials
60x100	Large equipment, commercial farm storage

Think about door placement before you pick the final size.

Drive-through bays help when you’re pulling a trailer or tractor. Side-entry doors can work better when the building sits near a driveway, fence, or gravel lane.

Commercial storage

Commercial storage needs more than square footage.

You have traffic flow, loading, inventory, employee access, equipment height, door openings, and local code to think about.

A 40x60 metal building is a common starting point for small business storage. Contractors use this size for tools, trailers, materials, and work trucks. Landscapers use it for mowers, blowers, spreaders, seed, and supplies. Small warehouses may need 50x80, 60x100, or larger.

Size	Best use
30x40	Contractor storage, small shop, tools
40x60	Inventory, trailers, work bays, equipment
50x80	Fleet storage, materials, light warehouse use
60x100	Larger warehouse, farm operation, equipment storage

For business use, check local rules early. Some areas treat commercial buildings differently than residential garages or carports.

Height planning

Metal building height is measured at the side wall, often called the leg height.

That number controls how tall your doors can be and how much clearance you have inside. Roof pitch and framing can add height at the center, but your usable door height still depends on the side wall and opening.

Use	Common side height
Cars and small storage	8 ft. to 9 ft.
Trucks and SUVs	9 ft. to 10 ft.
Tall trucks or small trailers	10 ft. to 12 ft.
RVs and fifth wheels	12 ft. to 16 ft. or more
Farm equipment	12 ft. to 16 ft. or more
Commercial equipment	Based on machine and door height

Always measure the tallest item going inside.

For trucks, include racks, ladder mounts, lights, and bed caps. For tractors, include ROPS, cab height, exhaust stack, loader arms, and attachments.

For RVs, measure the roof accessories. The AC unit counts. So does the antenna.

Door planning

Metal building doors decide how useful the building feels after it’s installed.

Too many buyers pick the building size and treat doors like an afterthought. Bad move.

Plan doors around the biggest thing you’ll move in and out. Then add room for steering and mistakes.

Door size	Common use
8x8	Small car, mower, ATV
9x8	Car or small SUV
10x10	Trucks, SUVs, small equipment
12x12	Taller trucks, tractors, trailers
14x14	RVs, farm equipment, commercial use
16x14	Wide RVs, equipment, business use

Metal building doors can be roll-up doors, walk-in doors, frame-outs, or custom openings. Windows help with light, but they take wall space away from shelves and storage.

For garages, think about daily movement.

A single wide door can make parking easier. Separate doors give each bay its own access. For shops, one large door plus a walk-in door is often cleaner.

For farm and business storage, drive-through doors can save a lot of backing, turning, and cussing.

Roof style choice

Roof style affects price, drainage, strength, and how the building looks on your property.

Most buyers choose from regular, boxed-eave, and vertical roof styles.

Roof style	Best fit	Notes
Regular roof	Basic storage and mild weather areas	Rounded edges, usually the lowest-cost style
Boxed-eave roof	Residential look on smaller buildings	A-frame look with horizontal roof panels
Vertical roof	Larger buildings, snow, heavy rain, long-term use	Panels run from peak to eave for better runoff

For most garages, workshops, RV covers, and larger custom metal buildings, the vertical roof is the better pick. Water and snow move off the roof more cleanly.

For wide buildings, long buildings, and areas with snow, start with vertical roof pricing.

Permits, wind load, and snow load

Metal building permits vary by city, county, building size, foundation, anchoring, and use.

Some areas allow small carports with simple rules. Some require engineered drawings, setbacks, inspections, specific anchors, and certified buildings. Rural land can still have county rules, HOA rules, floodplain rules, or utility easements.

Before you order, check:

Building department rules
Setbacks from property lines
Easements
HOA or neighborhood rules
Foundation requirements
Anchoring requirements
Wind speed requirements
Snow load requirements
Use type, such as residential, farm, or commercial

Garage Buildings has certified and engineered building options where local code requires them.

Wind-load certification is available up to 150 mph. Snow-load upgrades can be quoted where local code requires them.

Certification can affect framing, anchors, braces, roof style, and price. ZIP code matters because local code changes from one place to the next.

My size picks

Situation	My pick	Why
Cheapest basic 1-car storage	12x20	Covers the basics at 240 sq. ft.
Better 1-car garage	18x21	More room for doors, shelves, and gear
Better 2-car garage	24x26	Works better for trucks and daily use
Best homeowner all-around size	30x40	Vehicles, tools, storage, and shop space
Better landowner size	40x60	Tractors, RV, supplies, and work area
Small business storage	40x60	Good starting point for inventory and equipment
Bigger commercial storage	50x80	4,000 sq. ft. for fleet, materials, and bays
Large warehouse or farm use	60x100	6,000 sq. ft. for serious storage

FAQs

What size metal building do I need for 1 car?

Start with 12x20 for 1 small car. Choose 18x21 when you need room for shelves, bikes, a mower, or easier door clearance.

What size metal building do I need for 2 cars?

A 20x21 can fit 2 compact cars. A 24x26 is better for trucks, SUVs, storage, and daily use.

Is a 30x40 metal building big enough?

Yes. A 30x40 metal building gives you 1,200 sq. ft. It’s a strong size for homeowners who need vehicle storage, tools, shelves, and a work area.

What fits in a 40x60 metal building?

A 40x60 metal building gives you 2,400 sq. ft. It works well for larger shops, tractors, RVs, farm storage, contractor storage, and small business storage.

What size metal building do I need for an RV?

Measure the RV length, width, and full height first. Include AC units, vents, antennas, ladders, and roof accessories. Many RV owners start around 18x36, 20x41, 24x41, or larger depending on the RV.

How tall should my metal building be?

Cars often work with 8 ft. to 9 ft. side heights. Trucks may need 9 ft. to 10 ft. RVs, tractors, and commercial equipment may need 12 ft. to 16 ft. or more.

What roof style should I choose?

For basic small storage in mild areas, a regular roof may work. For garages, shops, RV covers, wide buildings, long buildings, rain, or snow, a vertical roof is usually the better pick.

Do I need a permit for a metal building?

Maybe. Metal building permits depend on your city, county, building size, foundation, anchors, and use. Check local rules before ordering.

Do I need wind load certification?

You may need wind load certification if your local code requires a certified building. Garage Buildings has wind-load certification available up to 150 mph.

Can I get snow load certification?

Yes. Snow-load upgrades can be quoted where local code requires them. This is common in areas with heavier snow or stricter building rules.

Can I customize the building size?

Yes. Garage Buildings sells custom metal buildings, metal garages, carports, barns, RV covers, workshops, utility buildings, warehouses, and commercial steel buildings. Buyers can choose width, length, height, roof style, colors, trim, doors, windows, anchors, insulation, panel layout, and certified wind or snow options.

Ready to size your metal building?

Garage Buildings can help you compare metal building sizes, metal garage sizes, metal carport sizes, roof styles, heights, door layouts, anchors, insulation, colours, trim, and certified options.

Free delivery and professional installation are included on eligible orders. Certified and engineered building options are available where local code requires them.

Still unsure about the size? Call Garage Buildings with your vehicle sizes, storage needs, and ZIP code. We’ll help you compare building sizes, roof styles, doors, wind ratings, snow loads, and installed pricing before you order.

What size metal building do I need?