What currency codes like USD and EUR mean (ISO 4217 explained)

USD, EUR, GBP, JPY. If you've used a currency converter, booked a flight, or looked at a bank statement from a trip abroad, you've seen these three-letter codes. They come from an international standard called ISO 4217, and once you know how they're built, most of them become easy to read at a glance.

What ISO 4217 is

ISO 4217 is maintained by the International Organization for Standardization. It gives every currency a unique three-letter code, and also a three-digit numeric code, for use anywhere currencies need to be identified unambiguously: bank transfers, card networks, accounting systems, airline tickets, and financial markets.

Symbols don't work for this, because many currencies share the same symbol. The "$" sign alone is used by the US, Canadian, Australian, New Zealand, Hong Kong, and Singapore dollars, as well as the Mexican, Chilean, Colombian, and Argentine pesos. The code removes any doubt: USD, CAD, AUD, and MXN can't be confused.

How the letters are chosen

For most national currencies, the first two letters are the country's two-letter ISO country code, and the third letter is usually the first letter of the currency's name:

• US + D: United States dollar (USD)
• GB + P: Great Britain pound (GBP)
• JP + Y: Japan yen (JPY)
• IN + R: India rupee (INR)
• MX + N: Mexico peso, where the N stands for "nuevo" (new), after the 1993 redenomination (MXN)
• ZA + R: South Africa rand, from the Dutch Zuid-Afrika (ZAR)
• CH + F: Swiss franc, where CH comes from Confoederatio Helvetica (CHF)

Some codes break the pattern. The euro is EUR, since it doesn't belong to a single country. When a country replaces its currency, the code often changes too, so the Turkish lira became TRY after the 2005 redenomination (previously TRL), and the Romanian leu became RON (previously ROL).

Codes that start with X

Codes beginning with X are for currencies or units that don't belong to a single country. Some are regional currencies shared by several countries, such as the West African CFA franc (XOF) and the East Caribbean dollar (XCD). Precious metals have codes too: gold is XAU and silver is XAG. The IMF's Special Drawing Rights are XDR. There's even XTS, reserved for testing, and XXX, meaning "no currency".

The numeric codes

Each currency also has a three-digit numeric code, often matching the country's numeric ISO code. The US dollar is 840, the euro is 978, and the pound is 826. These are used by some banking and card systems, and in countries that don't use the Latin alphabet.

Minor units

ISO 4217 also records how many decimal places each currency uses. Most use two (100 cents to a dollar), but the Japanese yen and Korean won use zero, and a few currencies, such as the Kuwaiti and Bahraini dinars, use three. That's why systems that handle money need to know the currency before they can display an amount correctly.

Where you'll see them

Every currency on this site is listed by its ISO code, and each one has a profile page with its symbol, subunit, and history. You can browse them all in the currencies section, or use the codes directly in the converter.