Container Size Guide: 20ft vs 40ft vs 40HC

Dimensions, payloads and internal volume for the three standard dry sizes, 20DC, 40DC and 40HC, with the decision rule for matching size to cargo density.

20ft Standard (20DC)

6.058 m external length, 33.2 m³ internal volume, rated payload 28,280 kg. National road weight limits often cap the load a truck may legally carry below that rating: check the route before loading to the maximum. The default choice for dense or heavy cargo, and for sites where access is tight.

40ft Standard (40DC)

12.192 m external length, 67.7 m³ internal volume, rated payload 26,700 kg. Shares the 2.591 m external height of a 20DC, which keeps it viable on height-restricted corridors.

40ft High Cube (40HC)

Same footprint as a 40DC with 30 cm more internal height, 76.3 m³ internal volume for the same payload ceiling. Dominant in new-build production and the standard choice for voluminous cargo and modification projects.

Choosing by stowage factor

Compare your cargo density against roughly 750 kg/m³. Above that threshold you reach the weight limit before filling a 20DC, so paying for extra volume adds nothing. Below it, the cost per cubic metre shipped favours a 40HC.

Choosing by stowage factor

What container sizes exist and which are the industry standards?

Five sizes carry the vast majority of world container traffic: 10DC (10 ft dry, a niche size used for spare parts, small storage or restricted access sites), 20DC (20 ft dry, the industry workhorse for dense heavy cargo, approx. 33 m³ interior), 40DC (40 ft dry standard height, approx. 67 m³), 40HC (40 ft high-cube with one extra foot of height, approx. 76 m³, now the dominant 40 ft type in new-build production), and 45HC (45 ft high-cube, a niche size for maximum-volume road transport, mostly in Europe). All follow the ISO 668 standard: exterior width is always 2.44 m (8 ft), exterior height is either 2.59 m (standard) or 2.90 m (high-cube), and length varies. Global fleet share is roughly 60% 40HC, 25% 20DC, 10% 40DC, 5% other combined. If you're new to containers: default to 20DC for heavy cargo and 40HC for voluminous cargo, the two together cover 85% of use cases.

What are the exact interior and exterior dimensions plus cubic capacity of each size?

Exterior × Interior × Volume, by size. 10DC: 2.99 × 2.44 × 2.59 m (exterior) / 2.83 × 2.35 × 2.39 m (interior) / approx. 16 m³ / 570 ft³. 20DC: 6.06 × 2.44 × 2.59 m / 5.90 × 2.35 × 2.39 m / approx. 33 m³ / 1,170 ft³. 40DC: 12.19 × 2.44 × 2.59 m / 12.03 × 2.35 × 2.39 m / approx. 67 m³ / 2,390 ft³. 40HC: 12.19 × 2.44 × 2.90 m / 12.03 × 2.35 × 2.70 m / approx. 76 m³ / 2,700 ft³ (about 13% more usable volume than 40DC thanks to the extra foot of height). 45HC: 13.72 × 2.44 × 2.90 m / 13.56 × 2.35 × 2.70 m / approx. 86 m³ / 3,060 ft³. Door opening width is roughly 2.34 m across all sizes, door opening height is 2.28 m (standard) or 2.59 m (high-cube). Floor payload zones are the corner castings, plan concentrated loads accordingly.

What's the max payload and road-legal weight by size?

Two numbers matter: MGW (max gross weight from the CSC plate, structural limit of the container) and road-legal payload (the chassis and traffic regulations of the destination country cap this below MGW). 10DC: tare 1.3 t, MGW 10 t, road-legal payload approx. 8-9 t. 20DC: tare 2.2 t, MGW 24 t, road-legal payload approx. 21-22 t in EU/US on a standard 3-axle chassis. 40DC: tare 3.7 t, MGW 30-32 t, road-legal payload approx. 26-27 t. 40HC: tare 3.9 t, MGW 30-32 t, road-legal payload approx. 26-27 t (same chassis limits as 40DC, the extra volume does not come with extra weight allowance). 45HC: tare 4.9 t, MGW 32-34 t, road-legal payload approx. 27-28 t. Key insight: on dense cargo (roughly >750 kg per cubic meter, the stowage threshold), you'll hit the road-legal weight limit long before you fill the box, which is why 20DC beats 40HC on cost-per-ton for machinery, tiles or bottled liquids. On light cargo you fill the volume first, 40HC wins on cost-per-cubic-meter.

Which container size should I pick for storage, shipping, modification or residential use?

Static ground storage: 20DC is the default (easier site access, lower per-unit cost, quicker to relocate if the layout changes); step up to 40HC only if you're storing bulky low-density items (furniture, event equipment, kayaks) or need one big footprint. Sea shipping: pick by cargo density using the 750 kg/m³ stowage threshold, dense goes 20DC, light goes 40HC. 45HC is a niche pick for European road transport where a longer trailer is permitted. Container modification (site cabin, workshop, container home, food truck): 40HC wins for anything you'll spend time inside, the extra 30 cm of ceiling changes the ergonomics dramatically and lets you fit two rooms plus a corridor in one box; 20DC works for single-room utility cabins or guardhouses. Residential / off-grid: 40HC is the industry standard for one-container homes; two 40HCs side-by-side gives roughly 60 m² of usable floor. Prestige projects (showroom, luxury build) often use Brand New or One-Trip 40HC for the paint uniformity, see the container-grades-explained guide for grade × size pairings.

What are the most common mistakes when picking a container size?

Four recurring traps. (1) Assuming bigger is cheaper per volume: it's not always true. In heavy-cargo shipping the road-legal payload cap makes 40HC a net loss vs 20DC on cost-per-ton. Compute your cargo's stowage factor before deciding. (2) Ignoring site access: a 40HC delivered on a tilt-bed truck needs 25-30 m of straight-line access; many urban or industrial sites don't have that clearance. Measure before ordering. (3) Confusing 40DC and 40HC: they share the same footprint but the height differs by 30 cm, critical for double-stack rail routes, some tunnels and warehouses with 2.59 m clearance where 40HC can't pass. Verify height clearance on the whole route. (4) Buying the wrong grade for the intended size: high-cube (40HC, 45HC) new-build production dominates modern grades, Brand New and One-Trip inventory is heavily 40HC and rarely 20DC. If you specifically need Brand New 20DC, allow more lead time and expect a price premium. Cross-check with the container-grades-explained guide and the 20dc-vs-40hc-container-size guide for detailed comparisons.