ISO 4217 is a standard first published by International Organization for Standardization in 1978, which delineates currency designators, country codes (alpha and numeric), and references to minor units in three tables:
- Table A.1 – Current currency & funds code list
- Table A.2 – Current funds codes 
- Table A.3 – List of codes for historic denominations of currencies & funds 
The ISO 4217 code list is used in banking and business globally. In many countries the ISO codes for the more common currencies are so well known publicly that exchange rates published in newspapers or posted in banks use only these to delineate the currencies, instead of translated currency names or ambiguous currency symbols. ISO 4217 codes are used on airline tickets and international train tickets to remove any ambiguity about the price.
The first two letters of the code are the two letters of the ISO 3166-1 alpha-2 country codes (which are also used as the basis for national top-level domains on the Internet) and the third is usually the initial of the currency itself. So Japan's currency code is JPY —JP for Japan and Y for yen. This eliminates the problem caused by the names dollar, franc, peso and pound being used in dozens of countries, each having significantly differing values. Also, if a currency is revalued, the currency code's last letter is changed to distinguish it from the old currency. In some cases, the third letter is the initial for "new" in that country's language, to distinguish it from an older currency that was revalued; the code sometimes outlasts the usage of the term "new" itself (for example, the code for the Mexican peso is MXN). Other changes can be seen, however; the Russian ruble, for example, changed from RUR to RUB, where the B comes from the third letter in the word "ruble".
In addition to codes for most active national currencies ISO 4217 provides codes for "supranational" currencies, procedural purposes, and several things which are "similar to" currencies:
- Codes for the precious metals gold (XAU), silver (XAG), palladium (XPD), and platinum (XPT) are formed by prefixing the element's chemical symbol with the letter "X". These "currency units" are denominated as one troy ounce of the specified metal as opposed to "USD 1" or "EUR 1". XBT is used by some exchanges for the cryptocurrency Bitcoin even though it is not ISO 4217 approved.
- The code XTS is reserved for use in testing.
- The code XXX is used to denote a "transaction" involving no currency.
- There are also codes specifying certain monetary instruments used in international finance, e.g. XDR is the symbol for special drawing right issued by the International Monetary Fund.
- The codes for most supranational currencies, such as the East Caribbean dollar, the CFP franc, the CFA franc BEAC and the CFA franc BCEAO. The predecessor to the euro, the European Currency Unit (ECU), had the code XEU.
The use of an initial letter "X" for these purposes is facilitated by the ISO 3166 rule that no official country code beginning with X will ever be assigned.
The inclusion of EU (denoting the European Union) in the ISO 3166-1 reserved codes list, allows the euro to be coded as EUR rather than assigned a code beginning with X, even though it is a supranational currency.
The ISO 4217 standard includes a crude mechanism for expressing the relationship between a major currency unit and its corresponding minor currency unit.
There is also a three-digit code number assigned to each currency, in the same manner as there is also a three-digit code number assigned to each country as part of ISO 3166. This numeric code is usually the same as the ISO 3166-1 numeric code. For example, USD (United States dollar) has code 840 which is also the numeric code for the US (United States).
Position of ISO 4217 code in amounts
The ISO standard does not regulate either the spacing, prefixing or suffixing in usage of currency codes.
In Bulgarian, Croatian, Czech, Danish, Dutch, Estonian, Finnish, French, German, Greek, Hungarian, Italian, Lithuanian, Polish, Portuguese, Romanian, Slovak, Slovene, Spanish and Swedish the order is reversed; the amount is followed by a hard space and the ISO 4217 code:
Note that, as illustrated, the order is determined not by the currency, but by the native language of the document context.
In 1973, the ISO Technical Committee 68 decided to develop codes for the representation of currencies and funds for use in any application of trade, commerce or banking.
Over time, new currencies are created and old currencies are discontinued.
The following is a list of active codes of official ISO 4217 currency names.In
The US dollar has two codes assigned: USD and USN (next day). The USS (same day) code is not in use any longer, and was removed from the list of active ISO 4217 codes in March 2014.
According to UN/CEFACT recommendation 9, paragraphs 8–9 ECE/TRADE/203, 1996,:
As of August 2018, there are no new codes planned to be added to the standard.
Non ISO 4217 currencies
A number of currencies are not included in ISO 4217, because these currencies are: (a) minor currencies pegged 1:1 to a larger currency, even if independently regulated (b) a legal tender only issued as commemorative banknotes or coinage, or (c) a currency of an unrecognized or partially recognized state. These currencies include:
- Alderney pound (1:1 pegged to the pound sterling)
- Cook Islands dollar (1:1 pegged to the New Zealand dollar)
- Faroese króna (1:1 pegged to the Danish krone)
- Guernsey pound (1:1 pegged to the pound sterling)
- Isle of Man pound (1:1 pegged to the pound sterling)
- Jersey pound (1:1 pegged to the pound sterling)
- Kiribati dollar (1:1 pegged to the Australian dollar)
- Maltese scudo (1:0.24 pegged to the euro)
- Sahrawi peseta of the Sahrawi Arab Democratic Republic in Western Sahara, sometimes given the code "EHP" but this has not been assigned by the ISO
- Somaliland shilling (state of issue is viewed as de jure part of Somalia, exchange rate not fixed)
- Transnistrian ruble (state of issue is viewed as de jure part of Moldova)
- Tuvaluan dollar (1:1 pegged to the Australian dollar)
- Zimbabwean bonds (1:1 pegged to the US dollar)
See Category:Fixed exchange rate for a list of all currently pegged currencies.
Despite having no official recognition in ISO 4217, the following non-ISO codes are sometimes used locally or commercially.
In addition, GBX is sometimes used (for example on the London Stock Exchange) to denote Penny sterling, a subdivision of pound sterling, the currency for the United Kingdom.
Recently, cryptocurrencies have unofficially used ISO codes on various cryptocurrency exchanges, for instance LTC for Litecoin, NMC for Namecoin and XRP for Ripple. SIX Interbank Clearing (a Maintenance Agency of ISO) is currently studying the impact and role of cryptocurrencies and other independent currencies on ISO 4217. 
Historical currency codes
A number of currencies were official ISO 4217 currency codes and currency names until their replacement by the euro or other currencies. The table below shows the ISO currency codes of former currencies and their common names (which do not always match the ISO 4217 names). These codes were first introduced in december 1988 after a request from the reinsurance sector was accepted