Postal code

A postal code (known in various countries as a post code, postcode, or ZIP code) is a series of letters and/or digits appended to a postal address for the purpose of sorting mail.

Germany was the world's first country with a postal code system in the early 1960s. The United States followed a couple of years later.

The majority of the world's national postal services have postal code systems. A few do not: for example, Ireland, although a national postal code system will be introduced in 2008. Hong Kong and Panama do not have postal codes.

Until June 2006, New Zealand's post code system was only used for the presorting of mail in bulk, not for addressing individual items, but this has been replaced by a new system in which postal codes will be required for all items.

Although postal codes are usually assigned to geographical areas, sometimes this is not the case: special codes may be assigned to institutions with large volumes of post, such as government agencies and large commercial companies. One example is the French Cedex system.

Usage conventions

Postal services often have their own distinctive formats and placement rules for postal codes (service areas, as a rule, are defined by national borders). In most English-speaking countries the postal code forms the last item of the address, whereas in most continental European countries it precedes the name of the city or town.

National prefixes

In some countries (for instance continental Europe, where many countries use the same postcode format of four or five numeric digits) it is usual to prefix the numeric postal code with a country code to avoid confusion. The codes used are generally based on Licence plate codes — for instance "D-" for Germany or "F-" for France — rather than ISO 3166-1 alpha-2.

Alphanumeric postal codes

Most postal codes are numeric. The few using alphanumeric postal code systems (with letters and digits) are:

Postal zone numbers

Before postal codes as described here were used, large cities were often divided into postal zones (or postal districts), usually numbered from 1 up within each city. The newer postal code systems often incorporate the old zone numbers, as with London postal district numbers, for example. Dublin, Ireland still uses postal district numbers, as postal codes are not used in the country at all. (An Post relies on OCR analysis of the entire address instead.) In New Zealand, Auckland, Wellington and Christchurch were also subdivided into postal zones, but these have fallen into disuse.

Postal codes in particular countries

Australia

Australian postcodes are numeric, consisting of 4-digits. They were introduced in 1967 by the Postmaster-General's Department (PMG), the predecessor of Australia Post. See this link for a history of the PMG / Australia Post : http://www.auspost.com.au/BCP/0,1080,CH2070%257EMO19,00.html

Canada

Canada uses 6-character alphanumeric postal codes of alternating letters and digits. They were introduced on a trial basis in Manitoba in 1971 and then expanded to the rest of the country between 1972 and 1974.

China

A postal code in Mainland China administered by the People's Republic of China has 6 different levels and 6 digits. From the left side, the first two digits show a province, a province-equivalent municipality, or a autonomous region. The third digit shows the postal zone. The fourth digit shows a prefectures or a prefecture-level city. The last two digits show a delivery post office.

Hong Kong and Macao have no postal codes. Taiwan Area administered by the Republic of China has a separate set of postal codes.

Finland

Finland uses 5-digit numeric postal codes. First two digits show the postal area and the last three the digits represent post office in the area. Corporations receiving large amounts of mail may have an own postal code. The special postal code 99999 is Korvatunturi, the place were Santa Claus (or Joulupukki in Finnish) is said to live.

France

France uses 5-digit numeric postal codes, the first two digits normally representing the Département.

Germany

German postal codes are numeric, consisting of 5 digits. Between 1990 and 1993 the old 4 digit postal codes in the former West Germany were prefixed with the letter "W", and postal codes in the former East, with "O" (for "Ost" or "East" in German).

India

India's postal codes are numeric, consisting of 6 digits, such as Kamboi 384230. They are known as Postal Index Numbers or PIN.

Netherlands

Postal codes in the Netherlands are alphanumeric, consisting of 4 digits, followed by two letters.

New Zealand

Since 1977, New Zealand has had a system of four-digit codes which were only required on mail sent in bulk, but in June 2006, a new system was introduced, which was required for all mail. There will be 1800 four-digit codes with a much finer granularity than the old codes, with each suburb and PostShop lobby having its own postal code. The first three digits will specify location and the last digit the type of delivery (street, PO Box Private Bag, or Rural delivery).

South Africa

South African postal codes are numeric, consisting of four digits. For a list of postal codes or to search by Location or Post Code see South African Post Office.

Soviet Union and Russia

Post codes in Russia are 6 digits long. To assist in their machine reading, envelopes are printed with something like a 9-segment outline for each digit, which the sender fills in.

Taiwan

Taiwan Area administered by the Republic of China uses postal codes of 3+2 digits. There are 368 sets of 3-digit codes for rural townships, urban townships, county-controlled cities, districts (Hsinchu City and Chiayi City have districts, but they are coded 300 and 600 respectively without 3-digit subdivisions), Pratas Islands, Spratly Islands, and Diaoyutai Islands claimed by the ROC while administered by Japan as Senkaku Islands. Omitting the supplemental 2 digits to write 3 digits is ordinarily okay, but a correct 5-digit code will speed up the mails.

The left-hand digit is for a large postal zone as follows:

0 Unused
1 Taipei City
2 Keelung City, Taipei County, Yilan County, Lienchiang County (Matsu), Diaoyutai Islands
3 Hsinchu City, Hsinchu County, Taoyuan County, Miaoli County
4 Taichung City, Taichung County
5 Changhua City, Nantou County
6 Chiayi City, Chiayi County, Yunlin County
7 Tainan City, Tainan County
8 Kaohsiung City, Kaohsiung County, Penghu County, Pratas Islands, Spratly Islands
9 Pingtung County, Taitung County, Hualien County

United Kingdom

UK postcodes are alphanumeric. These codes were introduced by the Royal Mail over a fifteen year period from 1959 to 1974. They have been widely adopted not just for their original purpose of automating the sorting of mail but for many other purposes — see for example The UK Postcode Lottery.

However, as the format of the codes does not achieve its objective of primarily identifying the main sorting office and sub-office they have been supplemented by a newer system of five digit codes called Mailsort. Mail users who can deliver mail to the post office sorted by mailsort code receive discounts, whilst delivery by postcode does not provide any incentive.

United States

The United States uses 5-digit numeric "ZIP codes". Since 1983, the US Post Office has been promoting an extended version called "ZIP+4", which adds a hyphen and 4 further digits after the main ZIP code to identify a smaller geographical area or single large user..

External links

UPU files for every country in PDF
Formats of all countries' postal codes
German postal codes in German language
French Belgium and Switzerland postal codes in French language
French postal codes in French language
International zip codes
GfK MACON: Worldwide post code maps for GIS
GRC Database Information: postal code links

Footnote

¹ Dublin is divided into postal districts, although these are regarded as sorting codes, rather than as postal codes.

Geocodes | Lists of postal codes | Postal system of Australia | Postal system of the United Kingdom

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