Free shipping calculator
Container Number Check
Paste full container numbers. The deterministic ISO 6346 calculation checks owner prefix, equipment category, serial and check digit, proposes the expected full number and exports a CSV audit.
Recommended next step
Parse the B/L and compare its container and seal evidence.
What this tool helps you check
- Validate ISO 6346 check digits
- Batch-check up to 100 container numbers
- Find transcription errors
- Export a validation audit
Calculation method
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.
Frequently asked questions
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.