GS1 / GTIN Check Digit Calculator and Validator
Compute the GS1 mod-10 check digit for a barcode number, or validate a full number in one click. Supports GTIN-8, GTIN-12 (UPC), GTIN-13 (EAN), GTIN-14, and SSCC-18. Built for GS1 barcode setup and serialization.
Enter the digits without the final check digit.
Try an example
Spaces are stripped automatically. Digits only.
Result
Validation result
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Check digit
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Full number
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Length
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Likely type
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GS1 check digit: FAQ
What is a GTIN check digit?
The check digit is the final digit of a GS1 barcode number. It is derived from all the other digits using a fixed formula, so a scanner or system can spot a mistyped or misread number. If the recomputed digit does not match, the number is invalid.
How is the GS1 check digit calculated?
Take the number without its check digit. Working from the rightmost of those digits, multiply alternately by 3, 1, 3, 1 and so on, with the rightmost multiplied by 3. Add all the products. The check digit is (10 minus (sum mod 10)) mod 10.
What is the difference between GTIN-13 and GTIN-14?
GTIN-13 (EAN-13) identifies a single consumer or trade item. GTIN-14 is 14 digits and typically identifies a packaging level, such as a case or carton, by adding an indicator digit in front of the item number. Both use the same mod-10 check digit rule.
Why does traceability need correct barcodes?
Kenya's PPB traceability programme relies on scannable GS1 identifiers on packs and cases. A wrong check digit produces a number that fails validation at serialization, aggregation, or a border scan, which can stall a consignment. Verifying the check digit before printing avoids costly rework.
Setting up GS1 barcodes or serialization?
We help pharmaceutical manufacturers, importers, and distributors set up GS1 identifiers, barcode artwork, and serialization ready for Kenya's authentication and traceability requirements.