The purpose of the Universal Equine Life Number (UELN) project was to develop a common system between all the organisations that register horses. This includes studbooks and equestrian federations, but also other national organisations that register horses for the purpose of identification, even if they are non-pedigree horses. Every organisation has its own database and independent system of identification, which makes the exchange of data very difficult.

The UELN is based on the horse's original registration number issued by the studbook or the registering authority of origin. Every original registration number can be converted into the corresponding UELN, which is internationally meaningful.

The UELN is a 15-digit alpha-numeric code:

- The first 3 digits indicate the country of the original database that registered the horse or foal. This may be a studbook of origin or a national horse identification authority.

- The next 3 digits indicate the database or organisation that registered the foal or horse.

- The remaining 9 digits stem from the national identification number given by the studbook or registering authority.