What Is an ISO Container? ISO Groups, Types & Size Codes
ISO 6346 CODE
An ISO container is a freight or storage container built to international standards (including ISO 668, ISO 1496, ISO 6346) that lets it be stacked, lifted, and transported interchangeably by any port, ship, or trucking company in the world. The “ISO” designation guarantees consistent external dimensions, corner-fitting locations, and structural strength ratings, which is why every ISO shipping container, regardless of manufacturer, fits the same cranes, chassis, and vessel cell guides. Once a shipping container is retired from ocean service, the same unit is commonly resold as an ISO storage container for on-site storage, workshops, or conversion projects, since it retains its weatherproof, stackable, ISO-compliant shell.
ISO 6346 is an international standard for the coding, identification, and marking of shipping containers used for freight transportation. Managed by the Bureau of International Containers (BIC), the standard provides a visual identification system that includes a serial number (with check digit ), the owner, country code, size, type, and equipment category of every shipping container.
Looking for ISO-certified shipping containers? Contact BSL Containers for new and used container solutions tailored to your operational requirements.
ISO Type Group
ISO Size Type
Code
Description
Code
Description
20GP
20G0
20G1
20HR
20H0
20PF
20P1
20TD
20T3
20T4
20T5
20T6
20TG
20T7
20T8
20TN
20T0
20T1
20T2
22BU
22B0
22GP
22G0
22G1
22HR
22H0
22PC
22P3
22P8
22P9
22PF
22P1
22P7
22RC
22R9
22RS
22R7
22RT
22R1
22SN
22S1
22TD
22T3
22T4
22T5
22T6
22TG
22T7
22T8
22TN
22T0
22T1
22T2
22UP
22U6
22UT
22U1
22VH
22V0
22V2
22V3
25GP
25G0
26GP
26G0
26HR
26H0
28TG
28T8
28UT
28U1
28VH
28V0
29PL
29P0
2EGP
2EG0
42GP
42G0
42G1
42HR
42H0
42PC
42P3
42P8
42P9
42PF
42P1
42PS
42P6
42RC
42R9
42RS
42R3
42RT
42R1
42SN
42S1
42TD
42T5
42T6
42TG
42T8
42TN
42T2
42UP
42U6
42UT
42U1
45BK
45B3
45GP
45G0
45G1
45PC
45P3
45P8
45RC
45R9
45RT
45R1
45UT
45U1
45UP
45U6
46HR
46H0
48TG
48T8
49PL
49P0
4CGP
4CG0
L0GP
L0G1
L2GP
L2G1
L5GP
L5G1
Shipping Container Information and How to Read ISO Containers' Markings
Every ISO shipping container carries a unique container number combining a 3-letter Owner Prefix (e.g. BSL), a 1-letter Equipment Identifier (U for freight containers), and a 6-digit Serial Number
1 digit for checking the validation of the container number.
The ISO container code (ISO 6346) is an international standard covering the coding, identification and marking of intermodal freight containers to standardise the name of the ISO container.
22G1 means 20 ft X 8 ft 6-inch General Purpose Container with passive vents at upper part of the cargo space.
The total weight of an ISO container including the weight can be packed.
Max. Gross Weight = Tare Weight + Max. Payload
The actual weight of an empty ISO container.
Tare Weight = Max. Gross Weight – Max. Payload
Max. weight that can be packed.
Max. Payload = Max. Gross Weight – Tare Weight
Max. volume that can be packed.
Like the identity card. Every container needs a valid CSC plate for international transport.
Listed the matters needing attention during the repair.
As BSL’s containers are made of Corten Steel, BSL leaves ‘Repair with “CORTEN” steel only’ label on the container as repair recommendation.
There are more than 10 container classification societies listed on International Code Council (ICC). BSL appointed classification societies are Lloyd’s Register (LR), Bureau Veritas (BV) & American Bureau of Shipping (ABS).
What are the different ISO container groups and types?
ISO containers fall into groups like general purpose (dry freight), reefer (refrigerated), open top, hardtop, tank, flat rack, platform, and ventilated. Each is identified by a specific two-letter type code such as GP, RT, UT or TN.
What do the letters and numbers in an ISO container code mean?
The first digit indicates length (2=20ft or 4=40ft), the second indicates height/width and the last two characters indicate the container type. For example, 45G1 is a 40ft high cube general purpose container.
What are the standard ISO shipping container sizes?
The most common sizes are 20ft and 40ft standard containers and 40ft High Cube containers, with less common sizes including 10ft, 45ft and 53ft units used mainly in domestic freight.
What is the difference between an ISO shipping container and an ISO storage container?
An ISO shipping container can also be used as an ISO storage container once it is deployed for on-site storage instead of cargo transportation. The container retains its durable, weatherproof and ISO-compliant construction. Depending on the intended application, some storage containers may be further modified with features such as personnel doors, ventilation systems, insulation, lighting, or shelving.
How do I find the ISO code on a container?
The ISO size/type code is stamped on the container's door or CSC data plate, directly below or beside the container number and check digit.