ISO 22P1 / 42P1 · Platform + end walls
Flat Rack Container Dimensions
A flat rack is a container reduced to its floor and two end walls — no roof, no sides. Cargo loads from above or from the side and lashes to rings along the base rails. It is the workhorse for machinery, boats, vehicles, transformers and project cargo.
Because the frame is massively reinforced, payloads beat every other container type: around 31 tonnes on a 20 ft and 40 tonnes or more on a 40 ft unit — heavy-duty versions go further.
The reinforcement costs weight: a 20 ft flat rack tares at about 2,740 kg and a 40 ft at roughly 5,480 kg, against 45,000 kg max gross for the forty. The 40 ft platform also sits higher, leaving about 1.95 m of cargo height under the top of the end walls versus 2.35 m on the 20 ft.
Point loads, not totals, are the number that bites in practice: 31 tonnes spread across the floor is fine, but the same weight on two machine skids will exceed the rated load per metre of floor. Heavy pieces ride on bedding timbers sized to spread the load — a detail carriers check before accepting the booking.
| Metric | Imperial | |
|---|---|---|
| External dimensions | ||
| Length | 6.058 m | 19′11″ |
| Width | 2.438 m | 8′ |
| Height | 2.591 m | 8′6″ |
| Internal dimensions | ||
| Length | 5.940 m | 19′6″ |
| Width | 2.345 m | 7′8″ |
| Height | 2.346 m | 7′8″ |
| Specification | ||
| Tare weight * | 2,740 kg | 6,041 lb |
| Max gross weight | 34,000 kg | 74,957 lb |
| Max payload * | 31,260 kg | 68,917 lb |
| TEU | 1 | — |
* Typical value — varies by manufacturer
| Metric | Imperial | |
|---|---|---|
| External dimensions | ||
| Length | 12.192 m | 40′ |
| Width | 2.438 m | 8′ |
| Height | 2.591 m | 8′6″ |
| Internal dimensions | ||
| Length | 12.060 m | 39′7″ |
| Width | 2.365 m | 7′9″ |
| Height | 1.955 m | 6′5″ |
| Specification | ||
| Tare weight * | 5,480 kg | 12,081 lb |
| Max gross weight | 45,000 kg | 99,208 lb |
| Max payload * | 39,520 kg | 87,127 lb |
| TEU | 2 | — |
* Typical value — varies by manufacturer
Over-width and over-height on a flat rack
Cargo wider or taller than the frame can ship on a flat rack as an out-of-gauge (OOG) load: the vessel simply leaves neighbouring slots empty. That flexibility is priced into the rate, so keep cargo within the platform envelope where possible.
Collapsible-end models fold flat for cheap repositioning — carriers stack four or five folded units in one container slot.
Flat rack vs open top
Both types exist for crane loading, so the choice comes down to what the cargo needs around it. An open top container keeps four full walls and a tarpaulin roof: the load stays weather-protected and sealable, but must fit within the standard internal width of about 2.35 m and the roof aperture.
A flat rack drops the walls entirely, so it takes over-width and extreme-weight pieces an open top never could — and lashing crews can work the cargo from all sides. The trade-off is exposure: flat-rack cargo needs its own weatherproofing (shrink-wrap, crates, marine coatings) and meticulous lashing. Rule of thumb: if it fits inside a box, use the open top and keep the protection; if it does not, the flat rack is the only container that works.
Frequently asked questions
How much weight can a flat rack carry?
Typical ratings are about 31 t payload on a 20 ft and 40 t on a 40 ft flat rack; specialised heavy-duty 20 ft units are rated to 45 t and more.
What is the loading area of a 20 ft flat rack?
About 5.94 m long by 2.35 m wide between the corner posts, with roughly 2.35 m of height to the top of the end walls. Payload is about 31,260 kg on a 2,740 kg tare.
What is the loading area of a 40 ft flat rack?
About 12.06 m long by 2.365 m wide between the corner posts, with roughly 1.95 m of height under the top of the end walls.
How much does a flat rack container cost?
In 2025–26, used flat racks typically sell for $3,500–7,000, with 40 ft and heavy-duty units at the top of the range. Supply is thin compared with dry boxes, so prices vary sharply by market and location.
Can cargo overhang a flat rack?
Yes — over-width and over-height cargo ships as an out-of-gauge (OOG) load. The vessel blocks adjacent slots to make room, and the freight rate rises to cover the lost capacity, so keep within the platform envelope where possible.
How is cargo secured on a flat rack?
With chains, wire or webbing lashed to rings and stake pockets along the base rails and corner posts — typically rated 2,000–5,000 kg per point on heavy-duty units — plus bedding timbers under concentrated loads and shrink-wrap or crating for weather protection.