Buying a shipping container sounds straightforward until you start looking at the options. New or used? 20ft or 40ft? Wind and watertight or Cargo Worthy? And can a delivery truck actually get to your site? These questions matter, and getting them wrong costs money.
This guide works as a proper decision framework, not just a list of container facts. Whether you need secure storage, a conversion project, or something going into international transport, the goal is to help you know exactly what to ask for before you spend anything.
If you’re still working out which type of unit fits your needs, browsing the range at Universal Containers shipping containers can help you see how different options are typically grouped by use, size, and condition.
Before you buy: a quick checklist
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What should you consider before buying a shipping container?
Start with the intended use
The use case should shape everything else. A container going into international transport has completely different requirements to one sitting on a farm for the next decade. A few scenarios to map out:
- Secure on-site storage: flexibility on condition, but base prep still matters
- Shipping or export: CSC plate and Cargo Worthy grade are non-negotiable
- Workshop or commercial use: cosmetics and structural integrity both count
- Conversion project: buy better than you think you need, you’ll thank yourself later
- Long-term static use on private land: check local planning requirements first
New vs used containers
The new vs used question gets oversimplified. Used is not automatically second-rate. Most buyers buying for storage do perfectly well with a used container. The real question is condition, not age.
One-trip units have crossed an ocean once from their origin. They’re as close to new as used gets: clean interiors, good doors, minimal rust. Expect to pay more. If appearance matters or you’re starting a conversion, they’re usually worth it.
Standard used containers vary more. Some are solid with minor cosmetic wear. Others have been hard-used. That’s why condition grading exists.
When condition matters more than price
Pay more when the container will be visible on a commercial site, used in export, or converted into something permanent. WWT or even Cargo Worthy used stock is usually fine for secure storage on private land where nobody’s looking at it daily.
Shipping container sizes explained
The most common shipping container sizes
The 20ft and 40ft account for the vast majority of sales. They’re ISO-standard, widely available, and most suppliers hold good stock of both.
- 20ft (6m): roughly 33 cubic metres of internal space. The most popular all-round size.
- 40ft (12m): roughly 67 cubic metres. Better for volume, bulkier items, or larger workshops.
- 45ft: less common but useful for specific high-volume requirements.
Which size is right for your project?
For most storage jobs, the 20ft is the easier choice. It’s cheaper to buy, cheaper to deliver, and more manageable to site. It fits on driveways and yards where a 40ft simply won’t.
If you’re filling it with furniture, machinery, or goods in bulk, the 40ft earns its extra cost quickly. For a conversion project like a home office or studio, 40ft gives you proper room to work with. A 20ft workshop conversion feels cramped once you add insulation and shelving.
Standard vs high cube
Standard containers are 8.5ft tall internally. High cube units add roughly a foot. That sounds minor until you’re standing inside trying to fit shelving, a mezzanine level, or just not ducking through a doorway.
High cube is worth the slight premium for any conversion. For plain storage, standard height is fine.
Shipping container condition grades buyers should know
One-trip
Used once for an ocean shipment from the country of manufacture (usually China). Best cosmetic condition, minimal rust, longest remaining lifespan. The choice for conversions, customer-facing sites, or any buyer who wants as close to new as possible without paying new prices.
Cargo Worthy / CSC plated
Cargo Worthy means the container has been inspected and certified fit for international shipping. The CSC (Convention for Safe Containers) plate is the physical proof of that certification.
If your container will ever be used in international transport, Cargo Worthy with a valid CSC plate is the grade you need. Without it, you’re not getting past port inspection.
Wind and Watertight (WWT)
Structurally sound, doors seal properly, no holes. It will keep your things dry. The CSC plate may have expired, but for static storage that never moves, you don’t need it.
WWT is the standard practical grade for most buyers who want secure, weatherproof storage at a sensible price. It’s the middle ground, and it works well there.
As-is or lower grade
Cheaper on paper, riskier in practice. You might get a solid unit or you might get doors that don’t close cleanly and a floor that needs work before it’s usable. Budget buyers who go this route should always inspect in person first.
Which grade should you choose?
- Export or international shipping: Cargo Worthy with valid CSC plate
- Best cosmetic condition: one-trip
- Solid secure storage, no frills: WWT
- Tight budget, willing to take some risk: lower grade, but inspect first
How to inspect a shipping container before buying
Exterior checks
- Look for dents, punctures, or signs of heavy impact
- Check for rust, particularly around seams, corner castings, and the roof
- Look for patches, which may suggest previous repairs to holes
- Check the roof is flat, not bowed or sagging
Door and seal checks
- Doors should open and close without forcing or lifting
- Locking gear should align cleanly without gaps
- Rubber door seals should be intact with no cracking or tearing
Interior and floor checks
- Do a daylight check: close the doors in daylight and look for light through the walls or roof
- Check the wooden floor for soft spots, holes, or signs of rot
- Smell matters: chemical odours or persistent damp are warning signs
- Look for staining that might indicate previous leaks or contaminated cargo
Questions to ask the supplier
- What is the container’s grade and has it been independently surveyed?
- Is it currently wind and watertight?
- Does it have a valid CSC plate?
- Has it been repaired or repainted?
- Can I view photos or inspect in person before paying?
- What delivery method do you use?
Delivery, access, and site preparation
This is where a lot of buyers come unstuck. Choosing the right container is pointless if the delivery truck can’t reach it or the base isn’t ready. Site preparation should happen before you order, not after.
Can the delivery vehicle access your site?
Most containers are delivered by tilt-bed trailer or crane-equipped vehicle. Before you confirm anything, check:
- Gate width: a tilt-bed needs around 3.5m minimum clearance
- Turning space: longer trailers need significant room to manoeuvre
- Overhead obstructions: trees, wires, and barn roof edges catch out more buyers than you’d think
- Drop point: the truck needs to get close enough to place the container where you actually want it
What base does a shipping container need?
Containers sit on four corner feet. They need level, solid support at all four points. If they’re unsupported in the middle or placed on soft ground, you get floor sag and door alignment problems over time.
- Concrete slab: ideal for permanent placement
- Concrete pads at each corner: a good, lower-cost alternative
- Timber sleepers: practical and widely used for static storage
- Compacted hardcore or gravel: workable for temporary use but check for settlement
Why site prep should happen before purchase
Delivery complications are expensive. Abortive visits cost money, restricted access causes delays, and a container placed wrong because the ground wasn’t ready is very hard to move cheaply. Sort the base and access before you confirm the order.
How much does a shipping container cost?
Prices move with availability, location, and market conditions. Any figure in an article will be out of date quickly, so treat this section as a guide to what affects price, not a price list.
What affects price?
- Size: 40ft units cost more than 20ft, typically by a meaningful margin
- Condition: one-trip costs more than WWT, which costs more than as-is
- Location: buying locally avoids significant delivery costs
- Specialist features: high cube, open-top, or refrigerated units command a premium
- Market conditions: container prices fluctuate with global shipping cycles
Why the cheapest container is not always the best value
A rock-bottom price can mean door alignment problems, floor replacement costs, or a container that needs repainting before it’s presentable. Factor in the total cost of getting it usable, not just the purchase price.
Do you need a standard or specialised shipping container?
Standard containers
General storage, transport, and most conversion projects. The 20ft and 40ft standard containers cover the majority of use cases.
Specialised containers
A few types worth knowing about:
- High cube: extra height for shelving, conversions, or tall equipment
- Side-opening: forklift-friendly loading without going in from the end
- Tunnel or double-door: access from both ends, useful for certain storage layouts
- Open-top: for crane-loaded cargo or items too tall for standard units
- Refrigerated: for temperature-controlled storage or transport
Are shipping containers a good long-term investment?
When buying makes sense
If you need storage for several years, buying nearly always beats hiring. Containers are low-maintenance, durable, and retain value reasonably well. Businesses that need on-site storage regularly, or buyers with conversion plans, get clear return on a purchase.
When hiring or a cheaper used unit may make more sense
Short-term overflow storage, temporary site use, or uncertain plans are all cases where committing to a purchase may not be the right move. Hiring keeps you flexible. A lower-grade used unit also works fine if you just need somewhere dry to put things for a year.
Buying a shipping container for conversion projects
What to look for if you plan to convert it later
Conversion changes the maths. A container that’s fine for storage may not be worth converting if the floor is soft, the walls have been patched, or the doors bind. When you’re planning to insulate, line, and finish a container, starting quality really does affect final cost.
- Look for a straight, uncorrected structure
- Better cosmetic condition means less prep and priming
- Fewer previous repairs means fewer weak points
- High cube units give you a more comfortable finished space
Why some buyers should start with a better-grade unit
The saving on a lower-grade container can disappear fast when you add floor replacement, structural repairs, and the extra priming needed to get a damp or patchy interior ready to finish. One-trip or good-condition used units often work out cheaper in total for conversion projects.
Final checklist before you order
Pre-order checklist
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FAQs
What size shipping container should I buy?
For most storage jobs, a 20ft unit is the right starting point. It’s cheaper, easier to site, and fits more access situations. Move to 40ft if you need the volume or you’re running a workshop conversion.
Is it better to buy a new or used shipping container?
For most storage applications, good quality used is perfectly fine. One-trip containers are the better choice for conversions, commercial use, or any situation where condition matters.
What does Cargo Worthy mean?
Cargo Worthy means the container has been inspected and meets the structural standards required for international shipping. It will typically carry a valid CSC plate. You need this grade if the container will be used in export.
What is a CSC plate on a shipping container?
The CSC (Convention for Safe Containers) plate is the official certification that a container meets international safety standards for transport. It has an expiry date. Without a valid plate, the container cannot be used in international shipping.
Is a WWT container good enough for storage?
Yes, for most static storage applications. Wind and Watertight means the container will keep water out and the doors seal properly. The CSC plate may have lapsed, but that only matters if you need to ship it internationally.
Can I put a shipping container on my land?
Usually yes for temporary use, but requirements vary depending on your local authority and how long it will be there. Permanent installation or conversion may need planning permission. It’s worth checking with your local council before committing to a purchase.
What should I check before delivery day?
Gate width, turning space, overhead clearances, and whether the base is ready. These are the four things that cause the most delivery problems. Sort them in advance.
Are 20ft or 40ft containers better value?
20ft containers are almost always better value per unit if you can work within the space. 40ft containers are better value per cubic metre if you genuinely need the volume.
