The four parts
Take MSKU 447102 5:
| Part | Example | Meaning |
|---|---|---|
| Owner code | MSK | Three letters registered with the BIC that identify the container's owner or operator. |
| Equipment category | U | U freight container, J detachable equipment, Z trailer or chassis. |
| Serial number | 447102 | Six digits chosen by the owner. |
| Check digit | 5 | Calculated from the first ten characters, so a mistyped character shows up. |
How the check digit works
- Convert each letter to a number: A = 10, then count up while skipping multiples of 11 (so K = 21, U = 32, Z = 38). Digits keep their value.
- Multiply the first character by 1, the second by 2, then 4, 8, 16 and so on, up to 512 for the tenth.
- Add the ten results and divide by 11. The remainder is the check digit; a remainder of 10 is written as 0.
You do not need to do this by hand: the free container number validator checks any number and shows the working.
Where to find it
The number is painted on the container doors and roof and printed on the bill of lading, packing list and booking confirmation. When they disagree, the number on the box is the one that counts.
Size and type codes
Next to the container number you will usually see a four-character size-type code, also from ISO 6346:
| Code | Means |
|---|---|
22G1 | 20 ft, 8 ft 6 in high, general purpose |
42G1 | 40 ft, 8 ft 6 in high, general purpose |
45G1 | 40 ft high cube (9 ft 6 in), general purpose |
45R1 | 40 ft high cube, refrigerated (reefer) |
The first character is the length, the second the height, and the last two the type.
Common mistakes
- Letter
Otyped for zero, orIfor one — owner codes are letters, the rest are digits. - Dropping the check digit, which leaves ten characters instead of eleven.
- Copying the seal number or the booking number by mistake.
The owner code also tells you the line: our carrier pages list the prefixes each major carrier uses.
Container tracking by carrier: Maersk, MSC, CMA CGM, Hapag-Lloyd, COSCO, ONE, Evergreen, HMM, Yang Ming and ZIM.