Add this line to your application's Gemfile:

gem 'gtin'

And then execute:

$ bundle

Or install it yourself as:

$ gem install gtin


This gem is all about validating GTIN-compatible identifiers and converting them to a standardized GTIN-14 representation. Supported input types include GTIN, EAN-13, UPC-A, UPC-E, ISBN-10, ISBN-13, and ISSN. Inputs must be strings containing only digits and include the check digit (see examples below).


GTIN.to_gtin('UPC', '123412341230') => '00123412341230'

GTIN.to_gtin('UPC', '1236432') => '00012300000642'

# ISBN-10
GTIN.to_gtin('ISBN', '0306406152') => '09780306406157'

# ISBN-13 with an incorrect check digit
GTIN.to_gtin('ISBN', '9780306406150') => GtinValidationError (invalid checksum)


After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install.

To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to .


Bug reports and pull requests are welcome on GitHub at License

The gem is available as open source under the terms of the MIT License.