Conex Container Dimensions: 20-Foot and 40-Foot Guide

A Conex container, shipping container, cargo container, and sea can are often different names for the same kind of steel box. The word you use matters less than the measurements you plan around. Before a container reaches your property, you need to know whether it will fit through the gate, sit where you want it, accept the equipment you need to store, and leave room for the delivery truck to work.

For most storage buyers, the choice comes down to a 20-foot unit or a 40-foot unit. Both are commonly eight feet wide outside. The real decision is about length, height, door access, and what the space needs to do after the first week. Use the figures below as practical planning numbers, then confirm the exact listing when a gate, rack, vehicle, or building edge leaves little room for error.

Quick Conex container dimensions chart

Freight containers are built around standard external dimensions. ISO 668 sets the classification and dimensions framework for Series 1 freight containers. Actual interiors and door openings can vary a little with age, manufacturer, floors, seals, and hardware, which is why a specific unit is the final authority.

Container type	Outside size	Approximate inside size	Practical fit
20-foot standard	20' L x 8' W x 8' 6" H	19' 4" L x 7' 8" W x 7' 10" H	Tools, equipment, and property storage
40-foot standard	40' L x 8' W x 8' 6" H	39' 5" L x 7' 8" W x 7' 10" H	Long materials, bigger storage plans, jobsite space
40-foot high cube	40' L x 8' W x 9' 6" H	39' 5" L x 7' 8" W x 8' 10" H	Tall shelving and upright equipment

The outside measurement tells you what needs to fit on the site. The inside measurement tells you whether the container will actually work for your equipment, racks, bins, and walking space. Treat the door opening as its own measurement, too. A tall item can have plenty of room once it is inside but still fail to clear the doorway.

What does “Conex” mean?

Conex is a common American term for a shipping container. You may also hear “container,” “cargo container,” “sea can,” or “ISO container.” When you are shopping locally, it is more useful to ask about length, height, condition, door layout, and delivery than to worry about which name appears on the listing.

For ordinary property storage, the common dry-container sizes are the ones worth comparing first. A 20-foot container gives you a compact, secure footprint. A 40-foot container gives you much more length without making the unit any wider. High-cube models add height, not width or length. That simple distinction helps keep a purchase decision grounded in the physical space you have.

20-foot Conex container dimensions

A standard 20-foot Conex container is roughly 20 feet long, 8 feet wide, and 8 feet 6 inches tall outside. Inside, expect about 19 feet 4 inches of length, 7 feet 8 inches of width, and 7 feet 10 inches of height. That creates nearly 150 square feet of floor space, enough for a serious amount of storage without taking over a smaller property.

A 20-footer is often the practical choice for tools, lawn equipment, side-by-side accessories, farm supplies, seasonal items, or a contractor’s compact jobsite setup. The key is organization. Put the large equipment in first, then use one wall for shelving or hanging tools and leave a route from the doors to the back. A container filled wall to wall may hold more for a day, but it becomes a chore every time you need the item at the rear.

A shipping container with clear access along its side at Wood Tech Structures

The limitation is length. Long lumber, pipe, ladders, and larger equipment can make a 20-foot unit feel crowded quickly. If the job needs separate zones for equipment, supplies, and daily work, the additional length of a 40-footer may save you from adding a second container later. Compare the two directly in the 20-foot versus 40-foot dimensions guide.

40-foot Conex container dimensions

A standard 40-foot Conex container is about 40 feet long, 8 feet wide, and 8 feet 6 inches tall outside. Its interior commonly measures close to 39 feet 5 inches long, 7 feet 8 inches wide, and 7 feet 10 inches tall. That is just under 305 square feet of floor area, nearly twice the usable floor space of a typical 20-footer.

The extra length changes the way you can organize the interior. A contractor might keep tools near the doors, place racks and materials through the middle, and reserve the far end for slower-moving stock. A farm can keep equipment accessible while separating feed, repair parts, and seasonal supplies. A larger property owner can store long materials without blocking the things that must come in and out regularly.

More length also means more delivery planning. Walk the route from the road to the pad. Look for tight turns, soft shoulders, fences, parked vehicles, branches, roof lines, and overhead utilities. Marking the footprint with stakes or paint often reveals a conflict before the delivery truck arrives. The 40-foot container buyer guide covers the selection and site questions in more detail.

A 40-foot cargo-worthy shipping container at Wood Tech Structures

Standard height versus high cube

Standard-height containers are about 8 feet 6 inches tall outside. High-cube containers are about 9 feet 6 inches tall outside, giving you roughly an extra foot of interior height. The footprint stays the same. A 40-foot high cube is still 40 feet long and 8 feet wide, but it can be easier to use with tall shelving, stacked goods, upright equipment, or a work area where headroom matters.

That extra height is useful only if the rest of the plan supports it. A high cube still has a narrow interior, and the door opening is smaller than the outside height. Measure the tallest and widest item at its true size, including handles, wheels, exhaust stacks, or brackets that cannot be removed. Then verify the particular door opening before you order. For a closer look at this choice, see the high-cube dimensions guide.

Door opening and interior clearance matter most

For day-to-day storage, the door opening can matter more than the listed outside dimensions. Standard cargo doors are commonly a little under eight feet wide and a little over seven feet high. That is generous for many tools and supplies, but it can be a hard limit for a tall cabinet, rack, machine, pallet, or vehicle. Do not assume an item will fit because the container itself is taller or wider.

Think through the loading path as well as the final storage spot. A mower needs a workable ramp angle and a clear approach. A pallet may need room for forks or a pallet jack. Long materials need a straight line through the doors. Double doors or side doors can make a long container easier to use, especially when you need regular access to a specific area rather than one deep storage lane.

Container cargo doors and loading area at Wood Tech Structures

When access is the real problem, door style belongs in the buying conversation. Wood Tech’s available shipping container listings show the actual units on hand, which is much more useful than choosing from a generic diagram. Look at the photos, ask about door operation and condition, and match the layout to the way the container will be loaded.

Choose the size from the job, not the cubic feet

Volume is useful for comparing containers, but it does not tell the whole story. A container is a long, narrow room with one or more door openings. The best size is the one that lets you retrieve the things you need without unloading half the container first. Start with the object that is hardest to move, then give it a realistic loading path and leave a usable aisle.

A 20-footer is usually enough when storage is compact, the property has limited room, and the longest items can fit comfortably inside. It is easier to place and easier to organize when the contents are mostly tools, mowers, boxes, and supplies. A 40-footer makes more sense when you need long materials, more than one storage zone, or room to grow without turning every visit into a reshuffling job.

For either size, write down the largest item, the longest item, and the things you reach for most often. That short list exposes the right layout quickly. It also makes a seller conversation more useful because you are choosing around the work the container must do, not simply buying the biggest steel box that fits the budget.

Condition changes the buying decision, not the footprint

Whether a container is one-trip or cargo-worthy does not change its nominal length, width, or height. It changes the condition you are evaluating. A one-trip container is commonly the better choice when appearance, near-new condition, and a cleaner exterior matter. A cargo-worthy container can be a sensible value when dependable weather-ready storage is the main goal.

Either way, inspect the real unit when you can. Look at the floor, door seals, locking hardware, roof, and corner areas. Open and close the doors. If you plan to add racks, insulation, or other improvements, think through that before delivery because every addition uses some of the interior clearance you just measured. The right condition is the one that suits the use, the property, and the level of finish you expect.

Plan the site around the outside dimensions

Do not prepare only a rectangle that matches the container. The container needs a stable, well-drained place to sit, room for its doors to swing, and enough working space for loading and maintenance. Delivery equipment needs an approach and an exit. A container that technically fits between two objects may still be difficult to unload, access, or keep in good working order.

Start with the road or driveway, not only the final pad. Check the entire path for turning room, low limbs, overhead lines, narrow gates, steep grades, and soft ground. Then check the destination for drainage, slope, future driveways, and the direction the doors should face. If you are unsure, take a few photos of the approach and intended spot before requesting a quote. It is much easier to solve an access question before a truck is scheduled.

How Wood Tech Structures can help

Wood Tech Structures helps Northeast Oklahoma buyers compare real 20-foot and 40-foot container options, including one-trip and cargo-worthy units when available. The team can help you connect the measurements on paper with the job, property, door layout, and delivery route you actually have.

Start by browsing current shipping container inventory. If you know what you need to store, how much room is available, and where the container should sit, share those details through the quote request page. A few practical details up front lead to a container that works better on delivery day and long after.

Frequently asked questions

What are the standard Conex container dimensions?

The most common Conex containers are 20 feet or 40 feet long and about 8 feet wide. Standard-height units are about 8 feet 6 inches tall outside, while high-cube units are about 9 feet 6 inches tall outside. Interior and door-opening measurements are smaller, so verify the specific unit when a tight fit matters.

How much usable room is inside a 20-foot Conex container?

A typical 20-foot dry container has about 19 feet 4 inches of inside length, 7 feet 8 inches of inside width, and 7 feet 10 inches of inside height. That works well for tools, equipment, seasonal property storage, and a compact jobsite setup when you keep a clear aisle.

How wide is the door on a Conex container?

A typical standard cargo-door opening is a little under 8 feet wide and a little over 7 feet high. Door hardware and container construction can change the exact clearance, so measure the item you need to load and confirm the actual container before delivery.

Is a 40-foot Conex container twice as big as a 20-foot container?

A 40-foot unit is roughly twice as long and has nearly twice the floor area and volume of a standard 20-foot unit. Both are normally the same outside width, so the choice is less about width and more about how much length, organization, and delivery room your project needs.

Does a high-cube Conex container have a bigger footprint?

No. A high cube usually has the same length and width as its standard-height counterpart. It adds about one foot of exterior and interior height, which helps with tall shelving and upright equipment, but it also makes overhead clearance more important on the delivery route.