Shipping Container for Sale
August 13, 2025
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November 11, 2025
Length of Shipping Containers: What You Need to Know
How much space do you actually need is one of those difficult but perennial questions.Our customers have many uses for containers; running a business, managing a renovation, or planning a big move.The length of shipping containers obviously makes a huge difference to storage capacity,but also cost of transport and usability around Bristol.
Most folks are aware that shipping containers come in different lengths, but pick the wrong length, and you’ll end up struggling for space or paying for unused space. AC&S makes things clear right from the start, so you get a container that actually fits.
The humble shipping container has a surprisingly rich history filled with quirky dimensional decisions and engineering compromises that might surprise you.
What is the usable length of shipping containers?
The "Almost 20-Foot" Mystery
The standard "20-foot" container isn't actually 20 feet long. The official dimension is 19 feet 10.5 inches (6.058 meters). Yes, that’s an odd 1.5-inch shortage. This seemingly arbitrary measurement actually serves a crucial engineering purpose.
When two 20-foot containers are placed end-to-end, there's a 3-inch gap needed between them. So shorting them by 1.5inches allows a single 40-foot container to fit precisely on top. The fittings on ships are positioned so that this gap creates perfect alignment for mixed container stacking.
Malcolm McLean's Original 35-Footer
Before the standard lengths we know today, a chap called Malcolm McLean designed 35-foot containers in 1956. This was revolutionary, as goods were previously shipped in all manner of containers. 33ft was the maximum trailer length allowed on Pennsylvania highways at the time. McLean's competitor, Matson, meanwhile opted for 24-foot containers, creating an early "format war" in the shipping industry.
McLean's practical approach stemmed from his trucking background; he understood that containers needed to work seamlessly across different transport modes, and Pennsylvania's highway restrictions were a limiting factor.
The Vietnam War Standardization Battle
The push for container standardization gained urgency during the Vietnam War when the U.S. military needed more efficient supply lines. McLean's company was still using 35-foot containers while competitors used 24-foot versions, creating logistical problems for the US military.
McLean made a bold business decision to secure the lucrative Vietnam shipping contract. He released his container patents royalty-free to the International Standards Organization (ISO). This act of apparent corporate altruism worked well for him. By standardizing the industry around his design principles, McLean ensured his company's long-term dominance.
The war drove home the importance of standardization, leading to the ISO 668 standard in January 1968, which established the 20-foot and 40-foot lengths we use today. Over 156,000 CONEX containers were shipped to Vietnam in the 1960’s, proving the effectiveness of containerization in military logistics.
Standard Container Lengths: The Industry Basics
When you hear about container sizes, three lengths will come up again and again: 10ft, 20ft, and 40ft. These standard lengths are the workhorses of the storage world.
10ft containers: The smallest standard option. About 3 metres long, good for tools, bikes, or overflow from the garage. Handy for tight job sites.
20ft containers: The all-rounder. Measures just over 6 metres, perfect for typical home moves, construction equipment, or most business stock.
40ft containers: Double the length, still 2.44 metres wide. Ideal for big moves, large commercial projects, or splitting into pop-up shops and offices.
Less common options pop up too, like 16ft, 24ft, and the giant 45ft units, but most projects stick to those main lengths for simplicity and cost.
Why Does the Length of Shipping Containers Matter?
Length determines floor space, stacking options, and where a container will (or won’t) fit on your Bristol garden, street, or jobsite. Pick something too short, and bulkier items get left behind. Go too long, and you’ll pay for space that never gets used.
Here’s how each shipping container length fits real needs
10ft: Quick fixes, small storage, project overflow, personal kit.
20ft: Moving house, medium business operations, builder tools, event gear.
40ft: Warehouse racking, big office moves, agricultural supply, customized modular builds.
Internal Length vs. External Length
You can’t fill a container right to the ends. Interior length is always a bit shorter due to steel walls and the framing for doors.
A 10ft container is 10’ (3.05m) outside, but more like 9ft 3 inches (2.83m) on the inside.
A 20ft container is 20’ (6.06 metres) outside, but closer to 19’ 3” (5.87 metres) inside.
A 40ft container is 40’ (12.19 metres) outside, but roughly 39’ 4” (12.01 metres) inside.
Widths are standard across most containers (2.44m / 8ft), though some custom units or “extra-wide” options are available on request. Just remember if you need precise space for racking, pallets, or furniture, always check the internal measurements.
High Cube vs. Standard Containers
While length usually gets top billing, don’t forget height. “High cube” containers add an extra foot (about 30cm) in vertical space. You still get the same floor area, but stacking gets easier and headroom improves. High cubes come in 20ft and 40ft versions.
Shipping Container Lengths: At Work in Bristol
Builders and event teams in Bristol often rent 40ft units for tools, decor, or pop-up bars. Some sites with tight access stick with 10ft containers, saving space and hassle.
At Alan Coward & Son, you’ll get advice from people who know Bristol’s roads and building sites. We help clients pick not just a container, but the right length, so traffic access, crane lifts, and local permits never become stumbling blocks. Lastly, and most importantly, we’ve got the expertise and equipment to get your container to you.
Length of Shipping Containers FAQ
Alan Coward & Son: Bristol’s Experts in Container Sizing
For fifty years, AC&S has helped Bristol clients pick the right length of shipping container for everything from site security to home moves or custom construction. Our experience means you always get advice that’s practical, cost-effective, and locally relevant. To have a chat about which container length fits your space, get in touch today.
