ISO 6346 Container Number Validator & Check Digit Calculator
Validate shipping container numbers and calculate check digits using the official international ISO 6346 Modulo-11 algorithm. Catch typographical errors before submitting customs declarations or transport bookings.
âī¸ Single Container Check Digit Calculator
đ Batch Manifest Validator
Paste a list of container numbers to check them for check digit accuracy in bulk:
How the ISO 6346 Algorithm Works
An ISO 6346 container number consists of four distinct components:
| Component | Format | Example | Meaning |
|---|---|---|---|
| Owner Code | 3 uppercase letters | TES |
Registered with the Bureau International des Containers (BIC) |
| Category Identifier | 1 uppercase letter | U |
U (all freight containers), J (detachable equipment), Z (trailers/chassis) |
| Serial Number | 6 numerical digits | 123456 |
Unique serial assigned by equipment operator |
| Check Digit | 1 numerical digit | 7 |
Modulo-11 validation digit derived from the first 10 characters |
Mathematical Check Digit Calculation
1. Letters AâZ are assigned values from 10 to 38 (multiples of 11: 11, 22, 33 are omitted).
2. Each of the 10 characters is multiplied by its positional weight: \(2^0, 2^1, 2^2, \ldots, 2^9\) (1, 2, 4, 8, 16, 32, 64, 128, 256, 512).
3. The sum of products is divided by 11. The remainder is the check digit (if remainder is 10, check digit is 0).
đ Standards & Technical References
- ISO 6346, Freight containers: coding, identification and marking, published by the International Organization for Standardization (iso.org) â.
- Bureau International des Containers (bic-code.org) â: registers the owner codes (first four letters) used in container numbers.