GTIN validator and check digit calculator

How is a barcode check digit calculated?

The last digit of every GTIN is a check digit, worked out from the digits before it. Scanners use it to catch mistyped or misprinted numbers.

The calculation uses Modulo 10. Working from the right, each digit is multiplied alternately by 3 and by 1; the results are added together, and the check digit is whatever brings that total up to the next multiple of 10.

Take the UPC-A number 70119720000, with the check digit missing. Multiplying and adding gives 65. The next multiple of ten is 70, so the check digit is 5, making the full number 701197200005.

Why is my barcode number invalid?

The usual causes are a mistyped digit, a number copied with spaces or hyphens still in it, a UPC-A pasted into a 13-digit field without its leading zero, or a number that was never a valid GTIN in the first place.

If you got the number from a supplier or an online listing and it won’t validate, it may not have been legitimately assigned. See our Retail Barcode Packages.

GTIN Formats

GTIN-8 (EAN-8)

  • Used for small retail items where space is limited
  • 8-digit code
  • Commonly used on small consumer goods and packaging
  • Example: 96385074

GTIN-12 (UPC-A)

  • The standard barcode format in North America
  • 12-digit code used primarily in the United States and Canada
  • Widely used in retail for product identification
  • Example: 701197200005

GTIN-13 (EAN-13)

  • International standard barcode format
  • 13-digit code used internationally for product identification
  • Example: 0701197200005

GTIN-14 (ITF-14)

  • Selling a product? Your retailers will likely request that an ITF-14 be placed on the cartons containing your product.
  • 14-digit code that can represent cases, cartons, or pallets
  • Generated from an EAN-13
  • Often used in logistics and supply chain management
  • Example: 10701197200002

 

ISBN (International Standard Book Number)

  • Unique identifier for books and book-like products
  • ISBN-13 uses GTIN-13 format
  • ISBNs are issued by a unique authority. In Canada, it’s Library and Archives Canada, and ISBNs are free to Canadian publishers.
  • Example: 978-3-16-148410-0

ISSN (International Standard Serial Number)

  • 8-digit code for periodical publications
  • Used for newspapers, magazines, and journals
  • ISSNs are issued by a unique authority. In Canada, it’s Library and Archives Canada.
  • Example: 0317-8471