ISO 6346 Container Size-Type Code Decoder

Paste the 4-character size-type code stamped on a shipping container (for example 22G1 or 45R1) and get a plain-English breakdown of its length, height, width and cargo type. Everything runs in your browser — nothing is uploaded. Free, instant, no sign-up.

Tip: this tool decodes the size-type suffix. To check that the 11-character container number and its check digit are valid, use the container number validator.

How it works

An ISO 6346 size-type code is exactly four characters. Each position carries a specific meaning, so the box "reads" like a tiny data sheet:

1. Character 1 — Length. Digits map to standard lengths (1 = 10 ft, 2 = 20 ft, 3 = 30 ft, 4 = 40 ft). Letters cover non-standard lengths (L = 45 ft, M = 48 ft, N = 49 ft, and so on).
2. Character 2 — Height & width. This single character encodes both. 0 = 8 ft 0 in, 2 = 8 ft 6 in, 4 = 9 ft 0 in, 5 = 9 ft 6 in (a "high cube"). Letters (C, D, E, L, M, N…) mean the container is wider than the standard 8 ft.
3. Characters 3–4 — Type. The first of the two is the category letter — G general purpose, V ventilated, R refrigerated (reefer), H insulated/heated, U open-top, P platform / flat-rack, T tank, B bulk, S named cargo. The trailing digit is a feature variant of that category.

Worked example: 22G1

Position	Char	Meaning
1 — Length	2	20 ft (6058 mm)
2 — Height & width	2	8 ft 6 in (2591 mm) tall, 8 ft (2438 mm) wide
3 — Category	G	General purpose (dry van)
4 — Feature	1	Passive vents at upper cargo space

22G1 = a standard 20 ft, 8 ft 6 in high general-purpose dry container.

Worked example: 45R1

Position	Char	Meaning
1 — Length	4	40 ft (12192 mm)
2 — Height & width	5	9 ft 6 in (2896 mm) — high cube, 8 ft wide
3 — Category	R	Refrigerated (reefer)
4 — Feature	1	Refrigerated and/or heated, removable equipment external

45R1 = a 40 ft high-cube refrigerated container (reefer).

Category letters at a glance

FAQ

What does a container size-type code like 22G1 mean?

It is the 4-character ISO 6346 size-type code. The first character is the length (2 = 20 ft), the second is height and width (2 = 8 ft 6 in tall, standard 8 ft wide), and the last two are the type (G1 = general purpose dry container with passive vents). So 22G1 is a standard 20 ft dry container.

What is the difference between 22G1 and 45R1?

22G1 is a 20 ft, 8 ft 6 in high general-purpose dry container. 45R1 is a 40 ft high-cube (9 ft 6 in) refrigerated container, or reefer. The size-type code tells you the box's dimensions and its cargo function at a glance.

Where do I find the size-type code on a container?

The 4-character size-type code is printed on the container doors and sides, usually just below or beside the 11-character owner and serial number (the BIC code). It is separate from the check digit. To validate the number itself, use our container number validator.

Decoded values follow public ISO 6346 size-type references and are provided as-is, without warranty. Some carriers use non-standard or legacy codes; always confirm critical shipping details against the operator's own documentation.