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    Calculator check digit

    Calculate the check digit for GS1 identification keys.

    Enter the number without the check digit

    0/12 digits entered

    What is the check digit?

    The check digit is the final digit of a GS1 identification key (GTIN, GLN, SSCC, GSIN, etc.) and is calculated from all the other digits in the key, using a globally standardised mathematical algorithm (the Modulo 10 algorithm).

    Its role is to allow scanners, IT systems and trading partners to automatically detect transcription or scanning errors. If one of the digits is wrong or two digits are transposed, the check digit will no longer match, and the code will be rejected before the error can propagate further down the supply chain.

    Why is the check digit important?

    • Automatically detects scanning or typing errors in GS1 keys.
    • Ensures data integrity across the entire global supply chain.
    • Enables instant validation of code integrity by POS, WMS and ERP systems.
    • Reduces product returns and invoicing errors caused by incorrect codes.
    • It is a mandatory component of every GS1 identification key.
    • It is calculated using a standard algorithm (Modulo 10) recognised internationally.

    Where is the check digit used?

    GTIN-8 / 12 / 13 / 14

    The Global Trade Item Number, for individual products or grouped packaging.

    SSCC

    The Serial Shipping Container Code – used for the unique identification of logistic units formed for delivery and transport

    GSIN

    The global shipment identification number, used in transport documents.

    GLN

    The Global Location Number – companies, departments, physical or functional locations.

    GRAI / GIAI

    Identification of returnable assets and the company's individual assets.

    GDTI / GSRN

    Identification of document types and relationships with service providers or beneficiaries.

    How do you calculate the check digit manually?

    1. 1

      Multiply the value of each position by its corresponding weight, alternating ×3 and ×1, starting from the right (the position immediately before the check digit has a weight of ×3).

    2. 2

      Add up all the results to obtain the sum.

    3. 3

      Subtract the sum from the nearest multiple of 10 that is greater than or equal to it. The result is the check digit.