Shipping Container Dimensions & Capacity Reference Guide
Standard ISO shipping container specifications, internal clearances, door opening apertures, tare weights, and operational payload limits.
Standard dry freight containers are available in three core sizes: 20' Standard (20GP, ~33 CBM), 40' Standard (40GP, ~67 CBM), and 40' High Cube (40HC, ~76 CBM).
While external dimensions are standardized by ISO 668, internal dimensions vary slightly across manufacturers and shipping lines. The maximum legal cargo weight is determined by the container's CSC plate and local highway axle-weight laws, not solely the container's internal cubic volume.
1. Standard ISO Container Specification Matrix
The values below represent the standard reference dimensions commonly encountered across major commercial shipping fleets:
| Metric Parameter | 20' Standard (20GP) | 40' Standard (40GP) | 40' High Cube (40HC) |
|---|---|---|---|
| Internal Length | 5,898 mm (19.35 ft) | 12,032 mm (39.47 ft) | 12,032 mm (39.47 ft) |
| Internal Width | 2,352 mm (7.71 ft) | 2,352 mm (7.71 ft) | 2,352 mm (7.71 ft) |
| Internal Height | 2,393 mm (7.85 ft) | 2,393 mm (7.85 ft) | 2,698 mm (8.85 ft) |
| Door Opening Width | 2,340 mm (7.67 ft) | 2,340 mm (7.67 ft) | 2,340 mm (7.67 ft) |
| Door Opening Height | 2,280 mm (7.48 ft) | 2,280 mm (7.48 ft) | 2,585 mm (8.48 ft) |
| Nominal Internal Volume | 33.2 CBM (1,172 CuFt) | 67.7 CBM (2,390 CuFt) | 76.3 CBM (2,694 CuFt) |
| Typical Usable Volume | 25 – 28 CBM | 54 – 58 CBM | 63 – 68 CBM |
| Typical Tare Weight | 2,280 kg (5,026 lbs) | 3,780 kg (8,333 lbs) | 3,980 kg (8,774 lbs) |
| Max Gross Mass (MGM) | 30,480 kg (67,200 lbs) | 30,480 kg (67,200 lbs) | 30,480 kg (67,200 lbs) |
| Max Container Payload | 28,200 kg (62,170 lbs) | 26,700 kg (58,863 lbs) | 26,500 kg (58,422 lbs) |
2. Why Equipment Tolerances Vary in Real Life
Many shippers assume all 40GP containers have identical interior measurements. In physical logistics, internal dimensions vary by up to 20–50 mm due to several mechanical factors:
- Corrugation Profiles: Side and roof corrugations vary in depth across manufacturers (such as CIMC, Singamas, and CXIC). Thicker corrugations increase structural stiffness but reduce interior width between ridges.
- Flooring & Linings: Container flooring typically consists of 28 mm laminated marine-grade plywood, but some older or refurbished boxes use bamboo composite boards or steel plate overlays, altering interior clearance height.
- Door Header Recess: The door top header beam drops lower than the container interior ceiling by approximately 100–115 mm. Cargo that fits vertically inside the box cannot be loaded if it exceeds the door opening height.
3. The CSC Safety Approval Plate
Under the International Convention for Safe Containers (CSC), every intermodal freight container carries a metal plate bolted to the left door. This plate is the legal authority on:
- Maximum Operating Gross Weight (Rating): Typically 30,480 kg (or 32,500 kg on reinforced modern units).
- Tare Weight: The empty weight of the container, stamped at manufacturing.
- Allowable Stacking Weight: The total load the container can support from containers stacked on top of it on a vessel (typically 216,000 kg).
Never rely on nominal website tables for legal cargo limits. Your certified Verified Gross Mass (VGM) submission under SOLAS regulations must adhere to the physical CSC plate and weight scale measurements.
4. Road Transport & Highway Axle Limitations
Even though a container is physically certified to carry significant payload under its CSC rating, highway weight regulations and bridge formulas frequently restrict total over-the-road weight.
Most jurisdictions enforce statutory gross vehicle weight limits (for example, US federal bridge formulas and European combination limits). On standard tandem trailers, the maximum legal cargo weight is often considerably lower than the container's physical structural rating.
Permissible cargo payloads depend on tractor tare, fuel weight, and chassis configuration (standard tandem vs specialized tri-axle). Always verify legal road limits with your local trucking carrier before loading dense cargo.
Need help choosing between container sizes?
Read our direct comparison guide or simulate packing online.