Editing Postal code (section)

== Presentation ==
[[File:Postal codes by country.svg|thumb|350px|right|Postal codes by country and digit-type.<br />'''Numeric digits''': <br /> &nbsp; {{legend inline|#87aade|3}} {{legend inline|#5f8dd3|4}} {{legend inline|#3771c8|5}} {{legend inline|#2c5aa0|6}} {{legend inline|#214478|7}} {{legend inline|#162d50|8}} {{legend inline|#0b1728|9}} {{legend inline|#070f1a|10}} <br />'''Alphanumeric digits''': {{legend inline|#2ca02c|6}} {{legend inline|#217821|7}} {{legend inline|#165016|8}}<br />'''Postal codes not in use''': {{legend inline|#e0e0e0|}}]]

=== Character sets ===
The characters used in postal codes are:
* The [[Arabic numerals|Western Arabic numerals]] "0" to "9"
* Letters of the [[ISO basic Latin alphabet]]
* Spaces, hyphens

==== Reserved and Excluded characters ====
[[Postal codes in the Netherlands]] originally did not use the letters 'F', 'I', 'O', 'Q', 'U' and 'Y' for technical reasons. But as almost all existing combinations are now used, these letters were allowed for new locations starting 2005. The letter combinations "SS" ({{lang|de|[[Schutzstaffel]]}}), "SD" ({{lang|de|[[Sicherheitsdienst]]}}), and "SA" ({{lang|de|[[Sturmabteilung]]}}) are not used, due to links with the [[Netherlands in World War II|Nazi occupation in World War II]].

[[Postal codes in Canada]] do not include the letters D, F, I, O, Q, or U, as the [[optical character recognition]] (OCR) equipment used in automated sorting could easily confuse them with other letters and digits. The letters W and Z are used, but are not currently used as the first letter. The Canadian Postal Codes use alternate letters and numbers (with a space after the third character), formatted ANA NAN.<ref name=GreatData.com>{{cite web|title=GreatData.com (a licensee of Canada Post data)|url=http://greatdata.com|access-date=8 February 2013|url-status=live|archive-url=https://web.archive.org/web/20130402154507/http://greatdata.com/|archive-date=2 April 2013}}</ref>

In Ireland, the [[eircode]] system uses the following letters only: A, C, D, E, F, H, K, N, P, R, T, V, W, X, Y. This serves to avoid confusion in OCR, and to avoid accidental double-entendres by avoiding the creation of word lookalikes, as Eircode's last four characters are random.

==== Alphanumeric postal codes ====
Most of the postal code systems are numeric; only a few are alphanumeric (i.e., use both letters and digits). Alphanumeric systems can, given the same number of characters, encode many more locations. For example, while a two digit numeric code can represent 100 locations, a two character alphanumeric code using ten digits and twenty letters can represent 900 locations.

The independent nations using alphanumeric postal code systems are:
* [[Argentina]] ([[Postal codes in Argentina|see table]])
* [[Brunei]] ([[Postal codes in Brunei|see table]])
* [[Canada]] ([[Postal codes in Canada|see table]])
* [[Eswatini]]
* [[Ireland]] ([[Postal addresses in the Republic of Ireland|see table]])
* [[Jamaica]] ([[Postal codes in Jamaica|see table]]) (suspended in 2007<ref>{{cite web |url=http://www.jamaicapost.gov.jm/corporate_news/pressrelease_07.htm |title=Post Code Project Suspended Indefinitely |work=Jamaica Post|date=12 February 2007 |access-date=4 March 2010 |url-status=dead |archive-url=https://web.archive.org/web/20100226125027/http://www.jamaicapost.gov.jm/corporate_news/pressrelease_07.htm |archive-date=26 February 2010 }}</ref>)
* [[Kazakhstan]] (since 2015)
* [[Malta]] ([[Postal codes in Malta|see table]])
* [[Netherlands]] ([[Postal codes in the Netherlands|see table]])
* [[Peru]] ([[List of postal codes in Peru|see table]]), the postal code format in Peru was updated in February 2011 to be of the format of five digits.
* [[Somalia]]
* [[United Kingdom]] ([[Postcodes in the United Kingdom|see table]])

Countries which prefix their postal codes with a fixed group of letters, indicating a country code, include [[Andorra]], [[Azerbaijan]], [[Barbados]], [[Ecuador]] and [[Saint Vincent and the Grenadines]].

=== Country code prefixes ===
[[ISO 3166-1 alpha-2]] country codes were recommended by the [[European Committee for Standardization]] as well as the [[Universal Postal Union]] to be used in conjunction with postal codes starting in 1994,<ref name="daCruz_ColumbiaUni">{{cite web| last =da Cruz| first =Frank| title =Frank's Compulsive Guide to Postal Addresses| publisher =Columbia University| date =17 May 2008| url =http://www.columbia.edu/kermit/postal.html#europe| access-date =4 June 2008| url-status =live| archive-url =https://web.archive.org/web/20080725104707/http://www.columbia.edu/kermit/postal.html#europe| archive-date =25 July 2008}}</ref> but they have not become widely used. [[Andorra]], [[Azerbaijan]], [[Barbados]], [[Ecuador]], [[Latvia]] and [[Saint Vincent and the Grenadines]] use the [[ISO 3166-1 alpha-2]] as a prefix in their postal codes.

In some countries (such as in [[continental Europe]], where a numeric postcode format of four or five digits is commonly used) the numeric postal code is sometimes prefixed with a [[country code]] when sending international mail to that country.

=== Placement of the code ===
Postal services have their own formats and placement rules for postal codes. In most English-speaking countries, the postal code forms the last item of the address, following the city or town name, whereas in most continental European countries it precedes the name of the city or town. When it follows the city, it may be on the same line or on a new line.

In [[Belarus]], [[Kyrgyzstan]], [[Russia]] and [[Turkmenistan]], it is written at the beginning of an address.{{citation needed|date=December 2017}} In [[Japanese addressing system|Japan]], it is written at the start of the address when written in Japanese, but at the end when the address is written in the Latin alphabet.