30.5 t67,200 lb
A fully loaded 40 ft shipping container weighs up to 30,480 kg (67,200 lb), the classic ISO maximum gross mass: about 3.8 tonnes (8,380 lb) of steel box plus roughly 26.7 tonnes of cargo. Many newer 40 ft boxes are rated for 32,500 kg (71,650 lb), and the ISO standard now allows up to 36,000 kg.
| ISO 668 maximum since 2016For all standard sizes except 10 ft | 36 t79,400 lb |
|---|---|
| Maersk 40 ft standard or high cube, max grossBox plus cargo | 32.5 t71,700 lb |
| Classic ISO maximum grossExactly 67,200 lb | 30.5 t67,200 lb |
| Maersk 40 ft high cube, empty9 ft 6 in tall | 3.81 t8,400 lb |
| Maersk 40 ft standard, empty8 ft 6 in tall | 3.63 t8,000 lb |
A container’s gross weight is its own empty weight (the tare) plus whatever is packed inside. A standard 40 ft steel box weighs about 3,800 kg (8,380 lb) empty. With the long-standing maximum gross of 30,480 kg, that leaves about 26,680 kg (58,820 lb) for cargo.
Maersk’s own spec sheet gives its 40 ft standard box a tare of 3,630 kg, a maximum gross of 32,500 kg and so a maximum payload of 28,870 kg. Its 40 ft high cube, a foot taller, weighs 3,810 kg empty and can take 28,690 kg of cargo. The tare of each box is painted on its door and printed on its safety approval (CSC) plate.
Inside, a 40 ft standard box is 12,032 mm long, 2,352 mm wide and 2,393 mm high, or 67.7 cubic metres. To reach the full 28,870 kg payload, the cargo has to average about 426 kg per cubic metre (28,870 ÷ 67.7). Light goods like clothing fill the space long before they reach the weight limit; heavy goods like steel or paper reach the weight limit with the box half empty.
The international standard for container sizes and ratings is ISO 668. For decades it rated 40 ft boxes at 30,480 kg (67,200 lb). A 2005 amendment raised 20 ft and 30 ft boxes to the same figure; before that, a 20 ft box was limited to 24,000 kg.
A further amendment in 2016 raised the ceiling for every standard size except 10 ft to 36,000 kg (79,370 lb). That is the most the standard allows, not what every box is built for. Carriers set ratings for their own fleets, and Maersk rates its 40 ft standard and high cube boxes at 32,500 kg.
The largest container ships are MSC’s Irina class, first delivered in 2023: about 400 m (1,312 ft) long, with a rated capacity of 24,346 TEU. One TEU is a 20 ft box, so that is space for roughly 12,170 boxes 40 ft long.
They could not all be fully loaded. 12,170 boxes at 30.48 tonnes each would come to about 371,000 tonnes, while an Irina-class ship has a deadweight (cargo, fuel, water and stores together) of just over 240,000 tonnes. Even with no fuel aboard, that works out to at most about 19.7 tonnes per 40 ft box on average (240,000 ÷ 12,170).
The record for the most containers actually carried on one voyage is 22,233 TEU, set by the ONE Innovation in September 2025 on a sailing from Singapore to Felixstowe, England.
Since 1 July 2016, the SOLAS convention has required a verified gross mass for every packed container before it can be loaded onto a ship. The shipper either weighs the packed container on certified equipment, or weighs all the cargo, pallets and packing separately and adds the tare of the box. The aim is to stow ships correctly and stop container stacks collapsing or boxes being lost overboard.
Empty, about 8,000 to 8,400 lb (3,630 to 3,810 kg). Fully loaded, up to 67,200 lb (30,480 kg) under the classic rating, or 71,650 lb (32,500 kg) for many newer boxes.
About 3.6 to 3.9 tonnes. Maersk lists 3,630 kg for its 40 ft standard box and 3,810 kg for its taller 40 ft high cube.
A 20 ft standard box weighs about 2,200 kg (4,850 lb) empty; Maersk lists 2,180 kg. It is rated for 30,480 kg gross, so it can carry about 28,300 kg of cargo, almost as much weight as a 40 ft box in half the space.
Usually about 26,700 to 28,900 kg (58,800 to 63,600 lb) of cargo, depending on the box’s tare and rating. Maersk’s 40 ft standard box takes up to 28,870 kg in 67.7 cubic metres.
The MSC Irina class is rated for 24,346 TEU, which is about 12,170 boxes 40 ft long. Its deadweight of about 240,000 tonnes means they cannot all be loaded to their maximum weight at once.
Last checked October 2, 2026.
