Customizing ISO 3166-1

Reserved and user-assigned code elements

ISO 3166-1 contains more than 230 country names and code elements. For some users of the standard that is not enough. They have additional coding needs. There are two ways to expand the number of code elements available:

• Reserved code elements are a tool used by the ISO 3166/MA to add flexibility to the coding system.
• User-assigned code elements are a tool users of ISO 3166-1 can put to work in their application.

Reserved code elements

In the course of the continuous updating and implementation of ISO 3166-1, some country code elements may become obsolete and some code elements which do not qualify for inclusion in ISO 3166-1 may be required in order to enable a particular user application of the standard.

To avoid transitional application problems and to aid users who require specific additional code elements for the functioning of their coding systems, the ISO 3166/MA may set aside code elements which it undertakes not to use for other than specified purposes during a limited or indeterminate period of time. These are called reserved code elements and their use is normally restricted to the application they were reserved for.

Code elements not included in the current version of ISO 3166-1 may be reserved by the ISO 3166/MA,

• as transitional reservations,as a consequence of changes in the standard. Code elements of this category may be used only during a transitional period while new code elements that may have replaced them are taken into use;
• as indeterminate reservations, if justified by their presence in other coding systems associated with ISO 3166-1 and where their reservation may facilitate the use of the system concerned. Any use outside such systems is prohibited and such code elements are expected eventually to be either eliminated or replaced by code elements in ISO 3166-1;
• as exceptional reservations, at the request of national ISO member bodies, governments and international organizations. This applies to certain code elements required in order to support a particular application, as specified by the requesting body and limited to such use; any further use of such code elements is subject to approval by the ISO 3166/MA.

Some of the reserved code elements may freely be used in applications of ISO 3166-1. So if you need a code element for a particular (country) name which is not officially listed in ISO 3166-1 it is a good idea to contact the ISO 3166/MA and to enquire whether there is a reserved code element for it. The list of the code elements reserved by the ISO 3166/MA is available on request. To receive a copy please contact the ISO 3166/MA.

User-assigned code elements

ISO 3166-1 specifies a series of code elements for user purposes which the ISO 3166/MA will never use in the updating process of the standard. To quote from ISO 3166-1:2006, clause 8.1.3 User-assigned code elements:

"If users need code elements to represent country names not included in this part of ISO 3166, the series of letters AA, QM to QZ, XA to XZ, and ZZ, and the series AAA to AAZ, QMA to QZZ, XAA to XZZ, and ZZA to ZZZ respectively and the series of numbers 900 to 999 are available."

These code elements are at the disposal of users who need to add further names of countries, territories or other geographical entities to their in-house application of ISO 3166-1. When exchanging data with users of ISO 3166-1 not connected to this particular in-house application the definition of these user-assigned code elements should be given. The incorporation of the complete ISO 3166-1 standard document in commercial products may be subject to a charge.