How this calculator works
A GTIN ends with a check digit that helps catch numeric entry mistakes. This calculator uses GS1 modulo-10 weighting to generate the final digit from a correctly sized base number, or to check a complete number. It does not create a registered product identifier or barcode image.
What the calculation does
Starting at the rightmost digit before the check digit, multiply alternating digits by three and one. Add the weighted digits, then choose the digit needed to reach the next multiple of ten. For validation, compare that digit with the final digit provided.
Important limitations
A valid check digit confirms only the arithmetic consistency of the entered digits. It does not prove GS1 allocation, company ownership, validity of the item, or authenticity of product packaging.
Common questions
Can I paste a code with leading zeros?
Yes. The input is treated as text and keeps leading zeros.
What number lengths are supported?
GTIN-8, GTIN-12 (UPC-A), GTIN-13 (EAN-13) and GTIN-14.
Does this issue an official GTIN?
No. Obtain registered identifiers through the appropriate GS1 member organization.