TRACKINGMCP · Container prefixes ↗
Paste any container number to check whether its ISO 6346 check digit is valid and decode the owner prefix. Runs entirely in your browser — nothing is sent anywhere.
A container number is 4 letters + 7 digits. The first 10 characters (owner prefix + 6-digit serial) determine the 11th — the check digit. Each character gets a value (digits as themselves; letters A=10, B=12, C=13 … skipping every multiple of 11), multiplied by 2 to the power of its position (1, 2, 4, 8 … 512). Sum them, take mod 11, and that is the check digit (a result of 10 is written as 0).
| Container number | Body (first 10) | Check digit | Owner |
|---|---|---|---|
MSCU6412104 | MSCU641210 | 4 | MSCU |
MAEU2100942 | MAEU210094 | 2 | MAEU |
TEMU3042129 | TEMU304212 | 9 | TEMU |
Under ISO 6346, each of the first 10 characters (4 owner letters + 6 serial digits) gets a value — digits are themselves; letters use A=10, B=12… skipping every multiple of 11 — multiplied by 2 to the power of its position (1, 2, 4, 8… 512). Sum them, take the remainder mod 11, and that remainder is the check digit (a remainder of 10 becomes 0).
The first three letters are the owner code and the fourth is the category identifier, almost always U for a freight container. Together the four-letter prefix identifies who owns the box — a shipping line or a leasing company. Enter a number above to decode the owner.
Eleven characters: four letters, then seven digits (a six-digit serial plus one check digit), e.g. MSCU 641210 5.
ISO 6346 check-digit algorithm. Owner decoding uses TrackingMCP's verified prefix registry. Updated 2026-07-14.