Shipping containers are built to a small number of ISO standards, which is exactly why they are so useful. Every unit is 8 ft wide, comes in one of two heights, and varies mainly in length. Once you understand those three variables you can specify the right container in about two minutes.
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Every standard size compared
The table below lists nominal ISO figures. Individual units vary a little by manufacturer and build year, so treat these as planning numbers and ask us for the exact measurements of the container you are quoted.
| Size | External L x W x H | Internal L x W x H | Floor area | Capacity | Tare weight |
|---|---|---|---|---|---|
| 10 ft standard | 10 ft x 8 ft x 8 ft 6 in | 9 ft 4 in x 7 ft 8 in x 7 ft 10 in | 72 sq ft | 565 cu ft | 2,870 lb |
| 10 ft high cube | 10 ft x 8 ft x 9 ft 6 in | 9 ft 4 in x 7 ft 8 in x 8 ft 10 in | 72 sq ft | 640 cu ft | 3,090 lb |
| 12 ft standard | 12 ft x 8 ft x 8 ft 6 in | 11 ft 4 in x 7 ft 8 in x 7 ft 10 in | 88 sq ft | 690 cu ft | 3,310 lb |
| 20 ft standard | 20 ft x 8 ft x 8 ft 6 in | 19 ft 4 in x 7 ft 8 in x 7 ft 10 in | 150 sq ft | 1,172 cu ft | 4,850 lb |
| 20 ft high cube | 20 ft x 8 ft x 9 ft 6 in | 19 ft 4 in x 7 ft 8 in x 8 ft 10 in | 150 sq ft | 1,320 cu ft | 5,180 lb |
| 30 ft standard | 30 ft x 8 ft x 8 ft 6 in | 29 ft 4 in x 7 ft 8 in x 7 ft 10 in | 226 sq ft | 1,766 cu ft | 6,610 lb |
| 40 ft standard | 40 ft x 8 ft x 8 ft 6 in | 39 ft 5 in x 7 ft 8 in x 7 ft 10 in | 305 sq ft | 2,390 cu ft | 8,270 lb |
| 40 ft high cube | 40 ft x 8 ft x 9 ft 6 in | 39 ft 5 in x 7 ft 8 in x 8 ft 10 in | 305 sq ft | 2,700 cu ft | 8,600 lb |
Door openings are roughly 7 ft 8 in wide by 7 ft 6 in high on a standard unit, and 8 ft 5 in high on a high cube. That door height is what usually decides whether a vehicle, a pallet stack or a piece of plant will actually fit through.
Why every container is 8 ft wide
Width is fixed by the ISO 668 standard so that containers stack and lock together on ships, trains and chassis anywhere in the world. Externally that is 8 ft, or 2.44 m. Internally you lose the wall thickness and the corrugation, leaving about 7 ft 8 in of clear width.
That figure matters more than most buyers expect. A standard UK or US pallet is 47 in by 39 in, so you can stand two pallets side by side across the width with a few inches to spare, but you cannot turn a pallet inside the container. Plan to load in from the doors and work backwards.
Standard height versus high cube
There are only two common heights. A standard container is 8 ft 6 in externally with about 7 ft 10 in inside. A high cube adds a foot, giving 9 ft 6 in externally and roughly 8 ft 10 in inside.
The extra foot is worth paying for when any of the following apply:
- You want to stand up comfortably inside a converted unit, or fit lighting and a ceiling below the roof line.
- You are stacking pallets two high, where 7 ft 10 in is often just short.
- You plan to insulate and line the walls and roof, which typically costs you three to four inches of internal height.
- You are storing tall plant, ladders, tyres on racking, or vehicles on ramps.
It is not worth paying for if the container will sit under a low canopy, pass through a height-restricted entrance, or hold nothing taller than shelving. Our high cube guide goes into the trade-offs in more detail.
What each length is genuinely good for
10 ft and 12 ft
Compact units that fit where nothing else will: a domestic driveway, a narrow yard, a school playground, a rooftop plant area. Popular for garden workshops, groundworks tool stores, bike and mobility scooter storage and site welfare kit. Light enough that a HIAB can usually place them without a crane.
20 ft
The default choice, and for good reason. 150 sq ft of secure floor holds the contents of a three-bedroom house, a full site tool inventory or roughly ten to eleven standard pallets on the floor. Fits most commercial yards and many driveways, and every haulier is set up to carry one.
30 ft
An uncommon but useful middle ground when a 40ft will not fit but a 20ft is not enough. Often specified for conversions where the layout needs an extra room, or for sites with a hard limit on length.
40 ft
Double the length for well under double the price per square foot, which makes it the cheapest secure storage you can buy per unit of volume. Best for pallet racking, vehicle storage, workshops and large conversions. Needs serious access: a 40ft delivery vehicle is around 55 ft long.
A three-question sizing method
What volume, honestly?
Measure or estimate the footprint of what you are storing and add a walkway. As a rule of thumb, a 20ft unit swallows the contents of a three-bedroom house, a 10ft handles a garage, and a 40ft handles a small warehouse bay. Buying one size up costs less than buying twice.
How much level ground?
You need the container footprint plus roughly 3 ft clear on the door end to swing the cargo doors fully open. Ground must be firm and level: compacted hardcore, concrete or tarmac.
Can the lorry get there?
This is what actually rules sizes out. See the access table below, then read the delivery preparation guide before you order.
Site access by container length
| Container | Typical vehicle length | Clear run-off for tilt-bed | Minimum overhead clearance |
|---|---|---|---|
| 10 ft | Around 26 ft | Around 30 ft | 16 ft |
| 20 ft | Around 40 ft | Around 55 ft | 16 ft |
| 30 ft | Around 50 ft | Around 75 ft | 16 ft |
| 40 ft | Around 55 ft | Around 95 ft | 16 ft |
Where that space does not exist, a HIAB lift or a crane can place the unit over an obstacle instead. Send us photographs of the approach with your enquiry and we will tell you what is possible before you commit.
Still not certain?
Tell us what you are storing, the postcode and roughly how the lorry would reach the spot. We will recommend a size and send a delivered price. If a smaller unit will do the job we will say so.
Sizing questions we get asked
Usually yes. A 20ft unit gives 150 sq ft of floor and 1,172 cu ft of volume, which comfortably takes the furniture and boxes from a typical three-bedroom home if it is packed properly and stacked to the roof.
On the floor, around ten to eleven standard pallets in a 20ft and twenty to twenty-two in a 40ft. Double-stacking roughly doubles those figures if the load and the pallet height allow it, which is where a high cube earns its money.
A 20ft unit takes most standard cars with very little room to spare. A 20ft high cube or a 40ft is a far more comfortable choice, especially if you want to open the doors or work on the vehicle inside.
Around 7 ft 8 in, which is the clear door opening width. Door height is 7 ft 6 in on a standard unit and 8 ft 5 in on a high cube.
They are far less common than 10ft, 20ft and 40ft units because they are not standard ISO shipping lengths in the same volumes. We do stock them, but availability moves quickly, so check the current listings or ask us.
Often, yes, because it needs a larger vehicle and more space to unload. That is why we quote transport against the specific unit and your postcode rather than applying a flat delivery charge.