A shipping container is 8 feet (2.44 meters) wide externally — and that width stays the same whether you’re buying a 20-foot unit, a 40-footer, or a high-cube. The internal width is slightly narrower at approximately 7 feet 8 inches (2.35 meters) due to corrugated steel walls. This standardization isn’t accidental; it’s part of an international spec that makes containers stackable, shippable, and interchangeable worldwide.
If you’re planning storage, a building project, or arranging delivery, understanding container width—and what it means for your access and usable space—makes the difference between a smooth project and an expensive problem.
External vs. Internal Width: Understanding the Difference
When someone asks “how wide is a container,” they’re usually thinking of the exterior—the footprint it takes up on your property. That’s the 8-foot external width set by ISO 668 (the international standard for container dimensions).
The internal width is narrower—approximately 7 feet 8 inches (92.5 inches / 2.35 meters). The ~4-inch difference on each side comes from the corrugated steel walls themselves, typically 40–45 millimeters thick. This matters when you’re loading cargo or planning an interior conversion.
Why this matters for you:
- For storage: you’ll fit pallets and shelving within that 7’8″ usable width.
- For a shipping operation: cargo loaded against the walls uses that internal dimension.
- For a building project (home, pool, office): that’s your starting dimension before you add insulation or framing, which eats into it further.
All Standard Containers Are the Same Width—Yes, Even 40ft
One of the most common misconceptions is that larger containers are wider. They’re not.
The width is identical across every standard size:
- 10-foot containers: 8 ft wide (external)
- 20-foot container rental: 8 ft wide (external)
- 40-foot storage containers: 8 ft wide (external)
- 40-foot High Cube: 8 ft wide (external) ← same width, not wider
The only dimension that changes with size is length (and for High Cube, height). This is by design—it keeps the corner castings, stacking patterns, and intermodal compatibility consistent worldwide.
The High-Cube Width Myth
High-Cube containers are often mistakenly thought to be wider, probably because they feel “bigger” when you see one next to a standard unit. In reality:
- High Cube = +12 inches of height only (9 ft 6 in tall vs. 8 ft 6 in standard).
- Width stays 8 feet.
- Length stays the same (40 feet for a 40ft HC, 20 feet for a 20ft HC).
If you need extra width, you’d need to combine two containers or look at specialized units—not upgrade to High Cube.
Door Opening Width
The door opening width is approximately 7 feet 8 inches (2.34 meters)—essentially the same as the internal width. This is the limiting dimension for loading large objects into a container. If you’re planning to slide equipment, machinery, or building materials through the doors, this is your effective width constraint.
Pro tip: Measure your load’s diagonal as well as its width; sometimes an item that’s 7’6″ wide and 5 feet tall needs to be tilted to fit through, and the container height becomes the limiting factor instead.
Why Is Every Container Exactly 8 Feet Wide? (ISO 668)
In 1968, the International Organization for Standardization (ISO) published ISO 668, which standardized container external dimensions to within a few millimeters. The 8-foot width wasn’t arbitrary; it was chosen because:
- Ship compatibility — containers stack 8–9 high on container ships, and 8 feet is the width that maximizes deck efficiency without exceeding crane lift ratings.
- Truck and rail chassis — standard US over-the-road containers fit on 8-foot-wide trailers; railway flatcars accommodate two rows of 8-foot-wide containers.
- Port infrastructure — spreader bars on ship cranes, stackers, and reach stackers are calibrated for 8-foot-wide corner castings.
- Interchangeability — an 8-foot width means a 20-footer stacks the same way as a 40-footer, a reefer aligns with a dry box, and a used unit from Rotterdam works with your domestic supply chain.
This standardization is why shipping containers became the dominant freight unit globally—rigid specs mean predictable handling and lower logistics costs.
Full Shipping Container Dimensions & Floor Area Comparison
Here’s the complete dimensions cluster so you can compare sizes at a glance:
| Size | External (L × W × H) | Internal Width | Internal Height | Ext. Floor Area | Int. Floor Area |
|---|---|---|---|---|---|
| 10ft Standard | 10′ × 8′ × 8’6″ | ~7’8″ | ~7’8″ | ~80 sq ft | ~75 sq ft |
| 20ft Standard | 20′ × 8′ × 8’6″ | ~7’8″ | ~7’10” | ~160 sq ft | ~150 sq ft |
| 40ft Standard | 40′ × 8′ × 8’6″ | ~7’8″ | ~7’10” | ~320 sq ft | ~300 sq ft |
| 40ft High Cube | 40′ × 8′ × 9’6″ | ~7’8″ | ~8’10” | ~320 sq ft | ~300 sq ft |
Note: Internal dimensions vary slightly by manufacturer and age. Figures represent standard ISO containers; verify with your supplier for custom or reefer units.
What the numbers mean:
- External floor area is the footprint on your property or truck.
- Internal floor area accounts for wall thickness and is your usable space for cargo or living area.
- Internal height is critical for tall stacks or vertical storage; High Cube gains 12 inches here, which makes a real difference for container homes and offices.
Usable Width for Building Projects (Container Homes, Pools & Offices)
If you’re planning to convert a container into a living space, office, or pool, the raw 7’8″ internal width is just the starting point.
Interior framing and insulation eat into both walls:
- Standard wall framing (2×4 studs + insulation + drywall) removes ~8–10 inches total from the width.
- After framing, your usable width drops to roughly 6’6″ to 6’10″—noticeably narrower.
- Some builders use thinner framing or no interior walls to preserve width, but you trade durability and insulation value.
This is why many container home projects use two containers side-by-side or stack them rather than working with a single narrow unit. A dual-container setup (two 20-footers) gives you ~15’4″ of usable width after framing—closer to a standard house.
See also: Container Homes Guide / Container Pool Build Guide for detailed conversion specs and real project examples.
Width & Delivery Access: What You Need to Know
When a container truck pulls up to your property, the width of the container itself is only one part of the equation.
Gate & Driveway Clearance
Container delivery trucks are typically 8 feet wide (the container itself) plus mirror assemblies and slight overhang. Plan for:
- Minimum gate width: 9 feet (adds 12–18 inches buffer per side).
- Driveway width: 10+ feet if the truck needs to angle or tilt to place the container.
- Overhead clearance: 14+ feet for most flatbed delivery trucks.
If your driveway is tight, notify the delivery company in advance—they may use a smaller crane or two-part delivery, which can add cost and time.
How to Measure Container Width in the Field
If you’re receiving a used container or verifying dimensions on-site:
- External width: measure between the outer corner posts (the vertical metal pillars at each corner).
- Internal width: measure between the inner steel walls, not touching the corrugation. This is slightly narrower than door-opening width in some units.
Slight manufacturer variations exist, so measure the specific unit if precision matters for your build or cargo fit.
Exceptions: Wider Containers (US Domestic & Specialty Units)
Standard 8-foot width covers ~99% of container use. But a few exceptions exist:
US Domestic 48ft & 53ft Containers
Containers used exclusively in US domestic trucking (not for international ocean freight) can be 8 feet 6 inches wide (2.59 meters). These are not ISO standard and won’t integrate with global supply chains or fit on container ships, but they maximize truck bed width for domestic land routes.
If you’re buying or renting, confirm whether you need ISO-standard 8-foot units or domestic non-stackable 8’6″ units. Mixing them in operations causes scheduling and handling problems.
Pallet-Wide & Reefer Containers
- Euro pallet-wide containers: approximately 8 feet 2 inches external to accommodate standard CHEP/Euro pallets more efficiently. These are uncommon in the US storage market but exist.
- Reefer (refrigerated) containers: have insulation that reduces internal width beyond the standard wall thickness. Usable width may be 7’4″–7’6″ internally—check with the supplier.
For storage and most building projects, these are edge cases. Stick with standard ISO 8-foot units unless you have a specific reason.
Frequently Asked Questions
Q: Is a 40-foot container wider than a 20-foot container?
A: No. Both are 8 feet wide externally. The 40-footer is twice as long (40 feet vs. 20 feet), but the width is identical. High-Cube versions are also 8 feet wide—they’re just 12 inches taller.
Q: How wide is the door opening?
A: Approximately 7 feet 8 inches (2.34 meters)—same as the internal width. This is your limiting dimension for loading large objects.
Q: What’s the internal width vs. the external width?
A: External is 8 feet; internal is roughly 7 feet 8 inches. The ~4-inch difference is corrugated steel walls on each side.
Q: Can you make a container wider by removing walls?
A: No. Removing load-bearing walls compromises structural integrity and container stacking safety. If you need more width, combine two containers or use a longer single unit.
Q: Are US 53-foot containers wider than standard 40-footers?
A: Yes—53-foot domestic containers are 8’6″ wide vs. the standard 8-foot ISO width. But they’re non-stackable and don’t fit on container ships, so they stay in domestic trucking only.
Q: What’s the floor area of a shipping container?
A: A 40-foot container has an external footprint of approximately 320 square feet and an internal usable area of about 300 square feet (accounting for wall thickness).
Q: How does internal width affect a container home?
A: The starting internal width is 7’8″, but adding insulation and wall framing reduces it to 6’6″–6’10”. This is why many container home projects use two containers to achieve livable room widths.
Ready to find the right container for your project? Get a quote today and our team will help you choose the perfect size and configuration.