Container glossary
What is max gross weight?
Max gross is the greatest total weight a container is rated for — the box plus everything in it — and it is 30,480 kg (67,197 lb) for most dry containers and 32,500 kg (71,650 lb) for many high cubes. It is a structural rating fixed when the container is built and approved, not a figure the shipper can choose.
Max gross weight by container size
| Container | Max gross | Tare | Payload |
|---|---|---|---|
| 20 ft container | 30,480 kg 67,197 lb | 2,230 kg 4,916 lb | 28,250 kg 62,281 lb |
| 40 ft container | 30,480 kg 67,197 lb | 3,740 kg 8,245 lb | 26,740 kg 58,952 lb |
| 40 ft high cube container | 32,500 kg 71,650 lb | 3,900 kg 8,598 lb | 28,600 kg 63,052 lb |
| 45 ft high cube container | 32,500 kg 71,650 lb | 4,800 kg 10,582 lb | 27,700 kg 61,068 lb |
| 20 ft reefer | 30,480 kg 67,197 lb | 3,080 kg 6,790 lb | 27,400 kg 60,407 lb |
| 40 ft high cube reefer | 34,000 kg 74,957 lb | 4,480 kg 9,877 lb | 29,520 kg 65,080 lb |
What the rating is tested against
A container type is approved by testing a prototype: lifted by its corners, stacked under load, racked sideways. The gross mass used in those tests becomes the rating, and it covers the conditions of a sea voyage with other loaded boxes on top. The manufacturer chooses that figure, within what the standard permits. Most containers in service are plated for 30,480 kg, many high cubes and newer twenties for 32,500 kg, and flat racks for more still; since its 2016 amendment ISO 668 allows a rating of up to 36,000 kg for every size except the 10 ft. The figures in the table above are these typical plated ratings, and a given box is good for exactly what its own plate says.
A 20 ft and a 40 ft plated alike therefore share one ceiling. The longer box simply spends more of it on its own steel, as the table above shows.
Reading MAX GROSS on the door and the CSC plate
It is the first line of the weight block on the right-hand door, in kilograms and pounds, sometimes abbreviated MGW or M.G.W. It appears again on the CSC plate as the maximum operating gross mass, and that plate is the authority: the figure on the unit in front of you overrides any table, including ours.
You meet it a second time on the weight declaration. A VGM higher than the max gross on the plate is not accepted for loading, whatever the cargo is.
Loading to the rating and forgetting the road
The rating says what the steel will bear. It does not say what a truck may carry. Road weight limits are set by each country for the whole vehicle — tractor, chassis, container and cargo — and they are usually reached well before the container’s own ceiling. A box packed to its max gross is fine on the ship and can be unlawful on the road at either end, which means a refused pickup, a fine, or cargo taken out and split into a second container.
A smaller confusion with the same cost: quoting max gross as if it were cargo capacity. The cargo figure is payload, which is max gross less tare. And pairing a 32,500 kg rating with a box that is actually rated 30,480 kg overstates what it can carry by two tonnes. Limits by mode are compared in the weight guide.
Frequently asked questions
What is the max gross weight of a 40 ft container?
Typically 30,480 kg (67,197 lb) for a standard 40 ft and 32,500 kg (71,650 lb) for a 40 ft high cube. Those are the usual plated ratings; the rating of a specific unit is on its CSC plate and may differ.
Is max gross the same as payload?
No — max gross includes the container’s own weight, payload does not. A 40 ft rated at 30,480 kg (67,197 lb) with a tare of 3,740 kg (8,245 lb) has a payload of 26,740 kg (58,952 lb).
Can a container be loaded above its max gross?
No — the rating is the limit the container was tested and approved for, and a declared mass above it is refused for loading. In practice the road limit of the country usually stops the load earlier.