Apostal code (also known locally in various English-speaking countries throughout the world as apostcode,post code,PIN orZIP Code) is a series of letters ordigits or both, sometimes including spaces or punctuation, included in apostal address for the purpose of sortingmail.
Although postal codes are usually assigned to geographical areas, special codes are sometimes assigned to individual addresses or to institutions that receive large volumes of mail, such as government agencies and large commercial companies. One example is the FrenchCEDEX system.
Postcode: Thissolid compound is popular in many English-speaking countries and is also the standard term in the Netherlands.
Postal index: This term is used in Eastern European countries such as Belarus, Moldova, Russia, Ukraine, etc.
PSČ: The standard term in Slovakia and the Czech Republic; PSČ is an acronym forPoštové smerovacie číslo (in Slovak) orPoštovní směrovací číslo (in Czech), both meaning postal routing number.
ZIP Code: The standard term in the United States and the Philippines; ZIP is anacronym forZone Improvement Plan.
1977 Soviet stamp promoting the use of postal codes
The development of postal codes happened first in large cities. Postal codes began with postal district numbers (or postal zone numbers) within large cities.London was first subdivided into 10 districts in 1857 (EC (East Central), WC (West Central), N, NE, E, SE, S, SW, W, and NW), four were created to coverLiverpool in 1864; andManchester/Salford was split into eight numbered districts in 1867/68. ByWorld War I, such postal district or zone numbers also existed in various large European cities. They existed in the United States at least as early as the 1920s, possibly implemented at the local post office level only (for example, instances of "Boston 9, Mass" in 1920 are attested[2][3]) although they were evidently not used throughout all major US cities (implementedUSPOD-wide) untilWorld War II.
By 1930 or earlier, the idea of extending the postal district or zone numbering plans beyond large cities to cover even small towns and rural locales had started. These developed into postal codes as they are defined today. The name of US postal codes, "ZIP Codes", reflects this evolutionary growth from a zone plan to a zone improvement plan, "ZIP". Modern postal codes were first introduced in theUkrainian Soviet Socialist Republic in December 1932,[4] but the system was abandoned in 1939. The next country to introduce postal codes was Germany in 1941,[5] followed by Singapore in 1950,[6] Argentina in 1958, the United States in 1963[7] and Switzerland in 1964.[8] The United Kingdom began introducing its current system inNorwich in 1959, but it was not used nationwide until 1974.[9]
Postal codes in Canada do not include the letters D, F, I, O, Q, or U, as theoptical 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.[10]
In Ireland, theeircode 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.
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:
In some countries (such as incontinental Europe, where a numeric postcode format of four or five digits is commonly used) the numeric postal code is sometimes prefixed with acountry code when sending international mail to that country.
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.
InJapan, 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.[13]
Postal codes are usually assigned to geographical areas. Sometimes codes are assigned to individual addresses or to institutions that receive large volumes of mail, e.g. government agencies or large commercial companies. One example is the FrenchCedex system.
Before postal codes as described here were used, large cities were often divided into postal zones or postal districts, usually numbered from 1 upwards within each city. The newer postal code systems often incorporate the old zone numbers, as withLondon postal district numbers, for example. Ireland still usespostal district numbers inDublin. In New Zealand,Auckland,Wellington andChristchurch were divided into postal zones, but these fell into disuse, and have now become redundant as a result of a new postcode system being introduced.
The first two digits of thepostal codes in Vietnam indicate aprovince. Some provinces have one, other have several two digit numbers assigned. The numbers differ from the number used inISO 3166-2:VN.
Map of Brazilian five-digit postalcodes ofSão Paulo state. Each color shows a set of administrative areas, and the hierarchy of codes relating indirectly to them.
In France the numeric code for the departments is used as the first two digits of the postal code, except for the two departments inCorsica that have codes 2A and 2B and use 20 as postal code. Furthermore, the codes are only the codes for the department in charge of delivery of the post, so it can be that a location in one department has a postal code starting with the number of a neighbouring department.
Codes defined indirectly to administrative borders
The first digit of thepostal codes in the United States comprises discrete states[18]. From the first three digits one can infer the state, with a few exceptions where an area is served by a central office in an adjacent state.
Similarly, inCanada, the first letter indicates the province or territory, although the provinces ofQuebec andOntario are divided into several lettered sub-regions (e.g. H forMontreal andLaval), and theNorthwest Territories andNunavut share the letter X.
Codes defined independently from administrative areas
The first two digits of thepostal codes in Germany define areas independently of administrative regions. The coding space of the first digit is fully used (0–9); that of the first two combined is utilized to 89%, i.e. there are 89 postal zones defined. Zone 11 is non-geographic.
Royal Mail designed thepostal codes in the United Kingdom mostly for efficient distribution. Nevertheless, people associated codes with certain areas, leading to some people wanting or not wanting to have a certain code. See alsopostcode lottery.
In Brazil the8-digit postcodes are an evolution of the five-digit area postal codes. In the 1990s the Brazilian five-digit postal code (illustrated),DDDDD, received a three-digit suffixDDDDD-SSS, but this suffix is not directly related to the administrative district hierarchy. The suffix was created only for logistic reasons.
Brazilian eight-digit postal codes – A city block and its faces
City blocks surrounded by streets, some streets with a different eight-digit postal code (suffixes 001 to 899)
Faces of acity block and their extension into its interior. Each color is an eight-digit postal code, usually assigned to a side (odd or even numbered) of a street.
Faces of a city block and their extension between city blocks. The same colors (polygons) indicate the same postal codes.
In thecode spatialization itis an error to associate the postal code to an individualland lot area: a lot may have 0, 1, 2 or more delivery points, with different codes.
The postal code assignment can be assigned to individualland lots in some special cases – in Brazil, they are named "large receivers" and receive suffixes 900–959. It is an error to associate the postal code with the whole land lot area (illustrated). A postal code is often related to aland lot, but postal codes are usually related to access points on streets. Small or middle-sized houses, in general, only have a single main gate, which is the delivery point. Parks, large businesses such as shopping centers and big houses, may have more than one entrance and more than one delivery point.
Czechoslovakia introduced Postal Routing Numbers (PSČ – poštovní směrovací čísla) in 1973. The code consists of 5 digits formatted into two groups: NNN NN. Originally, the first group marked a district transport centre, the second group represented the order of post offices on the collection route. In the first group, the first digit corresponds partly with the region, the second digit meant a collection transport node (sběrný přepravní uzel, SPU) and the third digit a "district transport node" (okresní přepravní uzel). However, processing was later centralized and mechanized while codes remained the same. After separation, Slovakia and the Czech Republic kept the system. Codes with an initial digit of 1, 2, 3, 4, 5, 6, or 7 are used in the Czech Republic, while codes with an initial digit of 8, 9, or 0 are used in Slovakia.
A code corresponds to a local postal office. However, some larger companies or organizations have their own post codes. In 2004–2006, there were some efforts in Slovakia to reform the system, to get separate post codes for every district of single postmen, but the change was not realized.
An example of a Postal Index Number fromkangra inHimachal Pradesh.4 indicates theWest postal zone,5 indicatesa postal sub-zone in Madhya Pradesh,6 indicates theUjjain sorting district,0 indicates theUjjain core area service route,01 indicates theUjjain Head Office as the delivery office.
Postal codes are known asPostal Index Numbers (PINs; sometimes as PIN codes) in India. The PIN system was introduced on 15 August 1972 by India Post. India uses a unique six-digit code as a geographical number to identify locations in India. The format of the PIN is ZSDPPP defined as follows:
Z – Zone
S – Sub-zone
D – Sorting District
P – Service Route
PP – Post Office
The first digit represents nine total zones: eight regional and one functional.
In Ireland, the new postal code system launched in 2015, known asEircode provides a unique 7-character alphanumerical code for each individual address. The first three digits are the routing key, which is a postal district and the last four characters are a unique identifier that relates to an individual address (business, house or apartment). A fully developed API is also available for integrating the Eircode database into business databases and logistics systems.
With a single exception, these codes are in the format:
ANN XXXX
The single exception is the Dublin D6W postal district. It is the only routing key area in the country that takes the format ANA instead of ANN:
D6W XXXX
While it is not intended to replace addresses, in theory simply providing a seven-character Eircode would locate any Irish delivery address. For example, the Irish ParliamentDáil Éireann is: D02 A272
Postal codes in the Netherlands, known as postcodes, are alphanumeric, consisting of four digits followed by a space and two letters (NNNN AA). Adding the house number to the postcode will identify the address, making the street name and town name redundant. For example: 2597 GV 75 will direct a postal delivery to Theo Mann-Bouwmeesterlaan 75,'s-Gravenhage (the International School of The Hague).
For domestic properties, an individual postcode may cover up to 100 properties in contiguous proximity (e.g. a short section of a populous road, or a group of less populous neighbouring roads). The postcode together with the number or name of a property is not always unique, particularly in rural areas. For example, GL20 8NX/1 might refer to either 1 Frampton Cottages or 1 Frampton Farm Cottages, roughly a quarter of a mile (400 metres) apart.
The structure is alphanumeric, with the following six valid formats, as defined byBS 7666:[19]
AN NAA ANA NAA ANN NAA AAN NAAAANA NAAAANN NAA
There are always two halves: the separation between outward and inward postcodes is indicated by one space.
The outward postcode covers a unique area and has two parts which may in total be two, three or four characters in length. A postcode area of one or two letters, followed by one or two digits, followed in some parts of London by a letter.
The outward postcode and the leading numeric of the inward postcode in combination forms a postal sector, and this usually corresponds to a couple of thousand properties.
Larger businesses and isolated properties such as farms may have a unique postcode. Extremely large organisations such as larger government offices or bank headquarters may have multiple postcodes for different departments.
There are 121 postcode areas in the UK, ranging widely in size fromBT which covers the whole of Northern Ireland toWC for a small part ofCentral London. Postcode areas occasionally cross national boundaries, such asSY which covers a large, predominantly rural area fromShrewsbury andLudlow inShropshire, England, through to the seaside town ofAberystwyth,Ceredigion onWales' west coast. There are a number of special purpose postcode areas that are "non-geographic" and which provide special routing instructions (such as parcel returns to online retailers). The three Crown dependencies and Gibraltar also use UK formatted postcodes. Some British Overseas Territories have adopted a single postcode for their territory that is very similar to the UK format.
In the United States, the basicZIP Code is composed of five digits. The first three digits identify a specificsectional center facility—or central sorting facility—that serves a geographic region (typically a large part of a state). The next two digits identify a specific post office either serving an area of a city (if in an urban area or large suburban area) or an entire village, town, or small city and its surrounding area (if in a small suburban or rural area).
There is an extended format of the ZIP Code known as theZIP+4, which contains the basic five-digit ZIP Code, followed by a hyphen and four additional digits. These digits identify a specific delivery route, such as one side of a building, a group of apartments, or several floors of a large office building. Although using the ZIP+4 offers higher accuracy, addressing redundancy, and sorting efficiency within theUSPS, it is optional and not widely used by the general public. It is primarily only used by business mailers.
For high volume business mailers using automated mailing machines, the USPS has promulgated theIntelligent Mail barcode standard, which is a barcode containing the ZIP+4 code plus a two digitdelivery point. This 11-digit number is theoretically a unique identifier for every address in the country.
States and overseas territories sharing a postal code system
French overseas departments and territories use the five-digitFrench postal code system, each code starting with the three-digit department identifier.Monaco is also integrated in the French system and has no system of its own.
The BritishCrown Dependencies ofGuernsey,Jersey and theIsle of Man are part of the UK postcode system. They use the schemes AAN NAA and AANN NAA, in which the first two letters are a unique code (GY, JE and IM respectively). Most of the Overseas Territories have UK-style postcodes, with a single postcode for each territory or dependency, although they are still treated as international destinations by Royal Mail in the UK, and charged at international rather than UK inland rates. The four other Overseas TerritoriesAnguilla,Bermuda,British Virgin Islands andCayman Islands have their own separate systems and formats.
TheCzech Republic andSlovakia still use the codes of the formerCzechoslovakia, their ranges not overlapping. In 2004–2006, Slovakia prepared a reform of the system but the plan was postponed and may have been abandoned. In the Czech Republic, there was no significant effort to modify the system.
In the United Kingdom, the non-conforming postal code GIR 0AA was used for theNational Girobank until its closure in 2003.[20] A non-geographic series of postcodes, starting with BX, is used by some banks and government departments.
In Finland, the special postal code 96930 is forKorvatunturi, the place where Santa Claus (Joulupukki inFinnish) is said to live, although mail is delivered to theSanta Claus Village inRovaniemi. The special postal code 99999 was formerly used.[24][25]
In Canada, the amount of mail sent to Santa Claus increased everyChristmas, up to the point that Canada Post decided to start an official Santa Claus letter-response program in 1983. Approximately one million letters come in to Santa Claus each Christmas, including from outside of Canada, and all of them are answered in the same languages in which they are written.[26] Canada Post introduced a special address for mail to Santa Claus, complete with itsown postal code:
SANTA CLAUS
NORTH POLE H0H 0H0
In Belgiumbpost sends a small present to children who have written a letter toSinterklaas. They can use the non-geographic postal code 0612, which refers to the date Sinterklaas is celebrated (6 December), although a fictional town, street and house number are also used. In Dutch, the address is
While postal codes were introduced to expedite the delivery of mail, they can be used for:
Finding the nearest branch of an organisation to a given address. A computer program uses the postal codes of the target address and the branches to list the closest branches in order of distance. This can be used by companies to inform potential customers where to go, byjob centres to find jobs for job-seekers, to alert people oftown planning applications in their area, and for other applications.[29]
Fine-grained postal codes can be used withsatellite navigation systems to navigate to an address by street number and postcode.
Geographical sales territories for representatives in the pharmaceutical industry are allocated based on a workload index that is based upon postcode.
Population data can be isolated, grouped and/or organized by postal code for statistical analysis.
This section needs to beupdated. Please help update this article to reflect recent events or newly available information. Last update: 2010(April 2021)
In some countries, the postal authorities charge for access to the code database. As of January 2010[update], the United Kingdom Government is consulting on whether towaive licensing fees for some geographical data sets (to be determined) related to UK postcodes.
^abChia, Joshua (13 July 2016)."Six-digit postal code system".Singapore Infopedia. National Library Board. Archived fromthe original on 5 October 2021. Retrieved3 October 2018.
^"BS7666 Address".Data Standards Catalogue. UK National Archives. 2 October 2009. Archived fromthe original on 28 January 2013. Retrieved15 August 2015.
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