Currency Code Table

The construction law is two ISO standards stacked. The first two letters come from ISO 3166, the country-code standard - JP for Japan, US for the United States, CH for Switzerland. The third letter, where possible, is the first letter of the currency name: JPY is Japan + yen, GBP is Great Britain + pound, CHF is Switzerland + franc. The design goal was killing ambiguity among the great recycled names: dollar describes the currencies of the US, Canada, Australia, New Zealand, Hong Kong and Singapore, and peso or pound each repeat too - but USD, CAD, AUD, NZD, HKD, SGD, MXN and ARS are all unique, self-describing strings. The one famous exception is EUR: the euro is supranational, but the EU holds a reserved entry in the country-code list, so the euro dodges the X-prefix rule that other non-country currencies get.

Because their practical unit is already the small one. A Japanese yen, Korean won or Vietnamese dong buys so little that no one quotes fractions of one - the smallest coin in each country is worth 1 unit, and prices are whole numbers: the minor unit simply does not exist, so ISO 4217 records zero decimals (JPY 392-0, KRW 410-0, VND 704-0). The Chilean peso joined the club when its inflation made one centavo pointless. At the other extreme sit the dinars - the Kuwaiti dinar records three decimals (KWD 414-3), pricing in thousandths, a legacy of oil-economy accounting where the base unit is worth several US dollars. The engineering lesson: the digits column is not a display preference, it is part of the amount - wire 1,000 KWD as 1,000.000 and 1,000 JPY as 1,000, and a form that assumes two decimals everywhere is already wrong.

X marks non-country money. When the first two letters cannot be a country - because the issuer is an institution or a group of them - ISO reserves the X prefix: XDR is the IMF Special Drawing Right, XOF and XAF are the West and Central African CFA francs, XCD is the East Caribbean dollar, and there are codes for precious metals held in reserve (gold, silver, platinum) under the same family. ISO also guarantees that no future country code will ever begin with X, which keeps the namespace permanently clean. That is why the euro is the exception that proves the rule: the EU negotiated a reserved EU entry in the country-code list specifically so its currency could be EUR - a mnemonic-friendly three letters - instead of an X-code like every other non-country currency.

No. ISO 4217 covers sovereign and officially sanctioned currencies - the active list is national currencies plus the institutional X-family, reviewed and amended by ISO's maintenance agency. Cryptocurrencies have no codes in the standard: exchanges and data vendors invent their own shorthand, some styled to look official by borrowing the X-prefix convention, but none of them are ISO assignments. The same disclaimer covers the codes you may meet that look nearly right: funds and non-cash instruments (various bond- and precious-metal codes) live in the same standard but are not spendable currencies. For any payment, invoice or API field, the safe habit stands: trust only the three-letter codes in the active list, and treat anything else as a vendor convention until the form says otherwise.