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Using the Check Digit Calculator

The check digit is the last number in a GS1 identification key, such as a GTIN-12 or GTIN-14. It is calculated using the other digits in the number and helps verify that the identifier has been entered correctly.

View the Steps Below on How to Use the Check Digit Calculator

Visit the Check Digit Calculator to get started.
 
  • First, enter your ID number in the ID Number field. For information about the required format for each identifier type, refer to the first question below
  • Click the Calculate button
  • The Check Digit will appear
Check Digit Screenshot

For information on how to construct the following GS1 Identifiers, view the Introduction the the Global Trade Item Number or the Introduction to the Serial Shipping Container Code.

Prefer to calculate the check digit yourself? Download the PDF instructions for step-by-step guidance.

Yes, if you click the "Let Us Assign Your GTIN" button, your GS1 US account will incorporate your GS1 Company Prefix, reserve the right number of digits for the Item Reference, and generate the check digit. 

If you already know the Item Reference you want to enter for this GTIN, click the "Choose a Specific GTIN" button. Enter the Item Reference, then click the "Get GTIN Check Digit" button, and the check digit is calculated for you.

If you already know the GS1 Company Prefix AND the Item Reference but want to learn how to calculate the check digit manually (outside of your GS1 US account), visit the GS1 US Check Digit Calculator page to calculate the check digit.

For a GTIN-12, which is the only GTIN that can be used in a UPC-A barcode, you should enter the following in the the GTIN-12 field:

  • U.P.C. Company Prefix (this is found on your GS1 Company Prefix Certificate)
  • Item Reference - this makes the GTIN unique from other GTINs you may have created
    Note: these two segments make up the first 11 digits of the GTIN-12.

If you are creating a "higher level" shipping/receiving item that contains multiple quantities of a single GTIN (such as an inner pack or case), you should enter the following in the GTIN-14 field:

  • Indicator Digit, which consists of a numeric value from 1 to 8
  • The same GS1 Company Prefix as the "each" GTIN that makes up the contents of this packaging item
  • The same Item Reference as the "each" GTIN that makes up the contents of this packaging item

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