در ایران کدپستی عددی ۱۰ رقمیست که ۵ رقم اول نشانگر کد رهسپاری (مشخصه شهر مقصد) و ۵ رقم دوم بیانگر کد توزیع (مشخصه مکانی مقصد) است. در ایران از عداد ۰ و ۲ به دلیل تشابه ظاهری به ترتیب با اعداد ۵ و ۳ استفاده نمیشود. کدپستی برای مشخص کردن یک آدرس پستی و به تبع آن مرتب کردن نامههای ارسالی وضع میشوند.
در فوریه ۲۰۰۵ از ۱۹۰ کشور عضو اتحادیه جهانی پست ۱۱۷ کشور کدپستی داشتند ایرلند و پاناما کدپستی ملی ندارند.
پیوند به بیرون[ویرایش]
"Post code" redirects here. For computer POST codes, see Power-on self-test.
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 French CEDEX system.
There are a number of synonyms for postal code; some are country-specific.
The development of postal codes reflects the natural evolution in which postal delivery grew more complicated as populations grew and the built environment became more complex. This process occurred first in large cities. The nucleus of a postal code idea thus began with postal district numbers (or postal zone numbers) within large cities. London was first subdivided into 10 districts in 1857, and Liverpool in 1864. By World War I or possibly earlier, such postal district or zone numbers existed in various European large 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), although they were evidently not used throughout all major US cities (implemented USPOD-wide) until World War II.
By 1930 or earlier the idea of extending postal district or zone numbering plans beyond large cities to cover even small towns and rural locales was in the air. This was the concept that would create postal codes as we define them today. (The very 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 the Ukrainian Soviet Socialist Republic in December 1932, but the system was abandoned in 1939. The next country to introduce postal codes was Germany in 1941, followed by Argentina in 1958, the United States in 1963 and Switzerland in 1964. The United Kingdom began introducing its current system in Norwich in 1959, but completed the nationwide introduction in 1974 only.
The characters used in postal codes are
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, SD and SA are not used for historical reasons.
Postal codes in Canada do not include the letters D, F, I, O, Q, or U, as the 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 alternates between a letter and a number (with a space after the 3rd character) in this format: A9A 9A9
This serves two purposes: to avoid confusion in OCR, but it also helps to avoid accidental double-entendre by avoiding the creation of word look-alikes as Eircode's last 4 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: with a 2 digit numeric code we could code 10 x 10= 100 locations. In contrast, with a 2 character alphanumeric code which uses 30 different characters, one has 30 x 30= 900 permutations.
The independent nations using alphanumeric postal code systems are:
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, 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 those of 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.
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 French Cedex system.
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 upwards within each city. The newer postal code systems often incorporate the old zone numbers, as with London postal district numbers, for example. Ireland still uses postal district numbers in Dublin. In New Zealand, Auckland, Wellington and Christchurch 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.
Codes defined along administrative borders
Format of 6 digit numeric (8 digit alphanumeric) postal codes in Ecuador, introduced in December 2007: ECAABBCC
Format of 5 digit numeric Postal codes in Costa Rica, introduced in 2007: ABBCC
In Costa Rica these codes are also used by the National Institute for Statistics and Census (INSEC).
The first two digits of the postal codes in Vietnam indicate a province. Some provinces have one, other have several two digit numbers assigned. The numbers differ from the number used in ISO 3166-2:VN.
Codes defined close to administrative borders
In France the numeric code for the departments is used in the first digits of the postal code, except for the two departments in Corsica 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 the postal codes in the United States defines an area including several states. From the first three digits (with some exceptions), one can deduce the state.
Codes defined independently from administrative borders
The first two digits of the postal 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 the postal 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 also postcode lottery.
In Brazil the 8-digit postcodes is an evolution of the 5-digits area postal codes. In the 1990s the Brazilian 5-digit postal code (illustrated),
A postal code is often related to a land lot, but this is not always the case. Postal codes are usually related to access points on streets. Small or middle-sized houses, in general, only have a single main gate which also functions as a delivering point. Parks, large businesses such as shopping centres, and big houses, may have more than one entrance and more than one delivery point. So the semantic of an address and its postal code can vary, and one land lot may have more than one postal code. In Brazil only the suffixes 900-959, that designate large post-receivers, can be assigned to lots.
In Ireland, the new postal code system launched in 2015, known as Eircode provides a unique code for each individual address. These 7-character alphanumerical codes are in the format: A99 XXXX
While it is not intended to replace addresses, in theory simply providing a 7-character Eircode would locate any Irish delivery address.
For example, the Irish Parliament Dail Éireann is: D02 A272
The first three digits are the routing key, which is a postal district and the last four characters are a unique identifier which relates to an individual address (business, house or apartment).
Allowed letters for positions: 123 4567
Position 1: A,C,D,E,F,H,K,N,P,R,T,V,W,X,Y
Unique Identifier (positions 4,5,6 & 7):
Defined in Eircode specifications : 
A fully developed API is also available for integrating the Eircode database into business database and logistics systems.
You can search for any Irish address' Eircode / postal code by using the search tool on the Eircode website : 
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, The Hague (the International School of The Hague).
Further information: Postcodes in the United Kingdom
For domestic properties the postcode refers to 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 apart. The postcode plus the first line of the address, however, is always unique (except where sub-properties occur[clarification needed]).
A9 9AA A9A 9AA A99 9AA AA9 9AA AA9A 9AA AA99 9AA
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 numbers, 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 about 100 postcode areas, ranging widely in size from BT which covers the whole of Northern Ireland to ZE for Shetland. Postcode areas may also cross national boundaries, such as SY which covers a large, predominantly rural area from Shrewsbury and Ludlow in Shropshire, England, through to the seaside town of Aberystwyth, Ceredigion on Wales' west coast.
Other countries allow equally precise coding. For example, in the United States, the delivery point barcode printed underneath an address by postal sorting equipment is typically derived from the last two digits of the house number and thus (at least theoretically) allows an unambiguous identification of every address in the country.
States and overseas territories sharing a postal code system
The British Crown dependencies of Guernsey, Jersey and the Isle 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 Territories Anguilla, Bermuda, British Virgin Islands and Cayman Islands have their own separate systems and formats.
San Marino and the Vatican City are part of the Italian postcode system, while Liechtenstein similarly uses the Swiss system, as do the Italian enclave of Campione d'Italia and the German enclave of Büsingen am Hochrhein, although they also form part of their respective countries' postcode systems. The Czech Republic and Slovakia base their systems on the codes of Czechoslovakia, their ranges not overlapping.
In Greenland the postal code 2412 is for Julemanden (Santa Claus)
In Canada the amount of mail sent to Santa Claus increased every Christmas, 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. Canada Post introduced a special address for mail to Santa Claus, complete with its own postal code:
Main article: List of postal codes
Non-postal uses and economic aspects
While postal codes were introduced to expedite the delivery of mail, they are very useful tools for several other purposes, particularly in countries where codes are very fine-grained and identify just a few addresses. Among uses are:
The availability of postal code information has significant economic advantages. 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 to waive licensing fees for some geographical data sets (to be determined) related to UK postcodes.