Free shipping calculator
ISO 6346 Container Number Validator
Paste one or up to 100 container numbers to verify their ISO 6346 structure and check digit. Invalid results show the expected full number for review and CSV export.
Recommended next step
Parse the B/L and compare its container and seal evidence.
Check Shipping Container Numbers
- Validate ISO 6346 check digits
- Batch-check up to 100 container numbers
- Find transcription errors
- Export a validation audit
ISO 6346 Check Digit Calculation
Letters are converted to ISO 6346 numeric values, multiplied by powers of two, summed and reduced to the expected check digit.
A valid check digit confirms number structure, not ownership, availability, physical condition or current tracking status.
Container Number Checker FAQ
Is the Container Number Check free to use?
Yes. The calculator is available without an account, and values entered into the form are calculated in the browser or by the tool endpoint required for the lookup.
How does the Container Number Check work?
Letters are converted to ISO 6346 numeric values, multiplied by powers of two, summed and reduced to the expected check digit.
Can I use the result for a booking or invoice approval?
Use the result as a transparent working calculation and verify it against the governing carrier tariff, contract or operational requirement. A valid check digit confirms number structure, not ownership, availability, physical condition or current tracking status.