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Container check digit

Check ISO 6346 check digits individually or in CSV batches.

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Calculate the check digit for a 10-character prefix or check a complete 11-character number.

Three owner letters · category U, J or Z · six digits · optional check digit. Spaces and hyphens are accepted.

Your check

Enter a number or load an example.

ISO 6346 check

Letters are converted to numerical values (A = 10, B = 12; multiples of 11 are skipped). The ten values are weighted from the left by 1, 2, 4 up to 512 and added. The remainder on division by 11 gives the check digit; remainder 10 becomes 0.

U = freight containers · J = detachable container equipment · Z = trailers and chassis. Example CSQU 305438 gives check digit 3.

Source for structure and meaning: BIC · Container Check Digit Calculator.