Free Freight Tool

Container Number Validator: ISO 6346 Check Digit

Validate shipping container numbers against the ISO 6346 format and check digit, and identify the owner prefix.

An ISO 6346 container number has a four-letter owner prefix, a six-digit serial number, and one check digit. The validator recalculates the check digit to catch typing errors.

How to use the Container Number Validator

  • Enter the full container number.
  • Review the format and check digit result.
  • Use the owner prefix to find the related tracking page.

How to read the result

Tool results are planning aids. Confirm final values with the carrier, forwarder, or customs representative when they affect cost, compliance, or acceptance.

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Frequently asked questions

What format does a container number use?

Four letters, six serial digits, and one check digit, as defined by ISO 6346.