A 40×40 metal building kit encloses 1,600 square feet, a square footprint 40 feet wide and 40 feet deep. That width holds four vehicles across or two bays of parking with a full shop behind them, and the matching 40-foot depth means nothing parks nose-to-tail and crowds the door. It is the size buyers reach for when a three-car garage runs out of room and the building needs to do real work: a trade shop, equipment storage, or a small commercial bay.
This guide sits under the metal building sizes pillar, where every footprint from a backyard shed to a commercial shell gets the same plain breakdown. Below: what fits inside a 40×40, the uses it suits, the frame and options you will see on a quote, the clear height to plan for, and an illustrative 2026 price range to carry into a supplier conversation.
1,600 square feet
What fits inside a 40×40 metal building
At 1,600 square feet, a 40×40 is squarely a shop, not a garage that happens to be large. The 40-foot width breaks into four roughly 10-foot bays, so you can line up four vehicles across the front, or hand half the building to parking and keep the rest as a permanent work floor. The square shape keeps depth generous: 40 feet leaves a full lane behind anything you park, plus a back wall for benches and racking.
That width and depth is what owners notice every day. Doors swing clear, a walking path survives when every bay is loaded, and oversized gear has somewhere to live without blocking a vehicle. Here is what the footprint comfortably handles:
- Four vehicles across the front, or two parking bays with the back half kept open for work.
- Two vehicles plus a full shop, with a long bench wall, a welder, a lift, and room to move stock.
- A large RV or boat beside daily drivers, with a rig up to roughly 40 feet ‹confirm› parked nose-in.
- A farm or contractor fleet under one roof: a tractor, a skid steer, a mower, trailers, and shelving.
- A two-bay service shop with a pair of lifts, a parts wall, and a clean floor lane between them.
Mind the door, not just the floor
A tall RV or a stacked equipment trailer can clear the 1,600-square-foot floor and still catch the door header. The roll-up opening sets your real clearance, so size door height around the tallest thing you store. The how to choose a size guide walks through measuring before you buy.
Uses
Common uses for a 40×40 footprint
The 40×40 is the size where a metal building stops being a big garage and becomes infrastructure. It is large enough for a working business yet still fits many rural and suburban lots, which is why it turns up so often across our metal building uses library. The footprint earns its keep as:
- A four-car or collector garage. Park a fleet and still walk between bumpers, a job it shares with our metal garage kits silo.
- A trade or fabrication shop. 1,600 postless square feet take a paint booth, a wash bay, and rolling storage at once.
- Equipment and implement storage. A working farm or contractor yard parks the whole fleet off the weather.
- A small commercial or service bay. Two lifts, a counter, and a parts room fit under one clear-span roof.
- A barn, studio, or event space. Insulate and line the interior and the square floor becomes a genuine room.
If you are still weighing footprints, the most popular sizes roundup shows where the 40×40 ranks against its neighbors, and the how to choose a size guide walks the width, depth, and height tradeoffs in order before you commit.
The frame
The typical frame and options
A 40-foot clear span is red iron territory. Light tube-steel kits stall at this width without an interior post, so a true 40-foot postless span rides on a bolt-up red iron frame that keeps the whole floor open. The frame you want tracks your snow and wind loads, a choice our construction types pillar breaks down in full.
Most 40×40 kits ship as a pre-engineered shell you assemble from numbered parts, and the options are where you fit it to the job. The usual menu:
- Doors. Two to four roll-up bay doors, commonly 10 to 14 feet wide ‹confirm›, plus one or two walk-in entries.
- Windows and vents. Daylight and airflow, which matter most once the space becomes a working shop or studio.
- Insulation. A must if you will heat or cool the building, and the first defense against condensation on the steel.
- Wall and roof upgrades. Heavier-gauge panels or a higher load rating for snow and high-wind country.
- Lean-to additions. A covered side bay for trailers or implements without enlarging the main footprint.
Confirm the load rating
Snow and wind ratings come from your local code, not the catalog photo. Whatever frame a kit ships on, make sure the engineering is stamped for your county before you buy. The widths and ratings here are illustrative starting points ‹confirm›, not a substitute for a sealed drawing.
Height
Clear height to plan for
Footprint is only half the spec. The eave height, the wall height at the side, sets how tall a door you can hang and how much usable wall you get, and it is the number buyers forget until a bay door turns out too short for the RV or the lift.
Most 40×40 shop and commercial kits offer eave heights from about 10 to 20 feet ‹confirm›, with 12 to 14 feet a common pick for a working shop. A taller eave near 16 feet ‹confirm› buys headroom for a two-post lift, a tall roll-up door, or a Class A RV, and it raises the roof peak with it. Plan the door clearance first, then size the eave to match:
- 10 to 12 foot eave. Standard vehicles, light equipment, and a clean four-bay garage.
- 12 to 14 foot eave. Lifted trucks, mezzanine storage, or a shop running an overhead crane on a light load.
- 16 foot and up. Tall RVs, stacked equipment, or a service bay with two-post lifts and high doors.
Cost
What a 40×40 kit costs in 2026
As an illustrative 2026 range, a basic 40×40 shell tends to land in the mid five figures, and a fully enclosed, insulated shop climbs from there. Treat these as planning numbers to confirm against a current quote, since steel pricing, your load rating, and door and insulation choices move the total the most:
| 40×40 configuration | Illustrative 2026 kit range | Notes |
|---|---|---|
| Open shell / cover style | $18,000 – $30,000 ‹confirm› | Frame, roof, partial or no walls |
| Enclosed shop shell | $28,000 – $48,000 ‹confirm› | Full walls, two to four bay doors |
| Insulated, finished shop | $45,000 – $70,000 ‹confirm› | Insulation, windows, upgraded doors |
Illustrative 2026 kit-only ranges. Confirm every figure with a current quote; foundation, delivery, and permits are separate.
Those figures are the kit alone. The slab, delivery, and any permit fees sit on top, and on a 1,600-square-foot build the concrete can be a meaningful share of the total ‹confirm›. For the full picture of what drives the number, see our metal building kit prices pillar, and use the metal building size chart to compare the 40×40 against other footprints on price per square foot.
FAQ
40×40 metal building kits: common questions
How big is a 40×40 metal building?
A 40×40 is 1,600 square feet, 40 feet wide by 40 feet deep. The 40-foot width is a clear span that breaks into four roughly 10-foot bays, and the matching 40-foot depth leaves a full working lane behind anything you park. It reads as a shop or a four-car footprint, not a large garage.
How many cars fit in a 40×40 garage?
Four standard vehicles fit across the 40-foot width, with roughly 10 feet per bay. Wide trucks parked together get tight on door clearance, so many owners run three parking bays and keep the fourth, plus the back depth, as a permanent shop. The square floor leaves room to walk between bumpers.
Is a 40×40 big enough for a workshop?
More than enough, and it still leaves room to park. With 1,600 postless square feet you can give two bays to vehicles and the rest to a full bench wall, a pair of lifts, and rolling stock. It is a common size for trade shops and small fabrication businesses.
Will an RV fit in a 40×40 building?
A rig up to roughly 40 feet ‹confirm› fits the floor with vehicles beside it, but roof height is the real limit. Tall Class A coaches want a 16-foot or taller eave and door, so confirm the clear door opening, not just the floor length, before you order.
How tall can a 40×40 metal building be?
Eave heights commonly range from about 10 to 20 feet ‹confirm›. A 12 to 14 foot eave suits a working four-bay shop, while 16 feet and up gives headroom for a two-post lift, a tall door, or an RV. Plan your door clearance first, then set the eave to match.
How much does a 40×40 metal building kit cost?
As an illustrative 2026 range, an open shell runs roughly $18,000 to $30,000 ‹confirm› and a fully enclosed, insulated shop climbs to $45,000 to $70,000 ‹confirm›. Those are kit-only figures; foundation, delivery, and permits are separate. Confirm with a current quote stamped for your address.
Does a 40×40 kit use tube steel or red iron?
A 40-foot clear span carries on red iron. A bolt-up red iron frame holds the full width open with no center post, which matters when you park four vehicles across or run lifts and wide loads. Tube-steel kits at this width usually need an interior post. See our construction types pillar for the full comparison.
Related guides
Keep reading
Compare the 40×40 with the footprints on either side, then check the hub for the full size lineup:
- Metal building sizes: the complete guide (the parent pillar).
- 30×40 metal building kits (ten feet narrower at 1,200 square feet).
- 40×50 metal building kits (the same width, ten more feet of depth at 2,000 square feet).
- 40×60 metal building kits (a long commercial or multi-bay shop at 2,400 square feet).
- 30×30 metal building kits (a smaller three-car footprint at 900 square feet).
- Metal building size chart (every footprint side by side).
