A currency is a standardization of
money
Money is any item or verifiable record that is generally accepted as payment for goods and services and repayment of debts, such as taxes, in a particular country or socio-economic context. The primary functions which distinguish money are: m ...
in any form, in use or
circulation as a
medium of exchange, for example
banknote
A banknote or bank notealso called a bill (North American English) or simply a noteis a type of paper money that is made and distributed ("issued") by a bank of issue, payable to the bearer on demand. Banknotes were originally issued by commerc ...
s and
coin
A coin is a small object, usually round and flat, used primarily as a medium of exchange or legal tender. They are standardized in weight, and produced in large quantities at a mint in order to facilitate trade. They are most often issued by ...
s.
A more general definition is that a currency is a ''system of money'' in common use within a specific environment over time, especially for people in a nation state. Under this definition, the
British Pound sterling (£),
euro
The euro (currency symbol, symbol: euro sign, €; ISO 4217, currency code: EUR) is the official currency of 20 of the Member state of the European Union, member states of the European Union. This group of states is officially known as the ...
s (€),
Japanese yen
The is the official currency of Japan. It is the third-most traded currency in the foreign exchange market, after the United States dollar and the euro. It is also widely used as a third reserve currency after the US dollar and the euro.
Th ...
(¥), and
U.S. dollars (US$) are examples of (government-issued)
fiat currencies. Currencies may act as
stores of value and be traded between nations in
foreign exchange market
The foreign exchange market (forex, FX, or currency market) is a global decentralized or over-the-counter (OTC) market for the trading of currencies. This market determines foreign exchange rates for every currency. By trading volume, ...
s, which determine the relative values of the different currencies. Currencies in this sense are either chosen by users or decreed by governments, and each type has limited boundaries of acceptance; i.e.,
legal tender laws may require a particular unit of account for
payments to
government
A government is the system or group of people governing an organized community, generally a State (polity), state.
In the case of its broad associative definition, government normally consists of legislature, executive (government), execu ...
agencies.
Other definitions of the term ''currency'' appear in the respective synonymous articles:
banknote
A banknote or bank notealso called a bill (North American English) or simply a noteis a type of paper money that is made and distributed ("issued") by a bank of issue, payable to the bearer on demand. Banknotes were originally issued by commerc ...
,
coin
A coin is a small object, usually round and flat, used primarily as a medium of exchange or legal tender. They are standardized in weight, and produced in large quantities at a mint in order to facilitate trade. They are most often issued by ...
, and
money
Money is any item or verifiable record that is generally accepted as payment for goods and services and repayment of debts, such as taxes, in a particular country or socio-economic context. The primary functions which distinguish money are: m ...
. This article uses the definition which focuses on the currency systems of countries.
One can classify currencies into three
monetary systems:
fiat money
Fiat money is a type of government-issued currency that is not backed by a precious metal, such as gold or silver, nor by any other tangible asset or commodity. Fiat currency is typically designated by the issuing government to be legal tende ...
,
commodity money, and
representative money, depending on what guarantees a currency's value (the
economy
An economy is an area of the Production (economics), production, Distribution (economics), distribution and trade, as well as Consumption (economics), consumption of Goods (economics), goods and Service (economics), services. In general, it is ...
at large vs. the government's
precious metal reserves). Some currencies function as
legal tender in certain
jurisdiction
Jurisdiction (from Latin 'law' and 'speech' or 'declaration') is the legal term for the legal authority granted to a legal entity to enact justice. In federations like the United States, the concept of jurisdiction applies at multiple level ...
s, or for specific purposes, such as payment to a government (
taxes), or government agencies (fees, fines). Others simply get traded for their economic value.
The concept of a
digital currency has arisen in recent years. Whether government-backed digital notes and coins (such as the
digital renminbi
Digital renminbi ( zh, 数字人民币; also abbreviated as digital RMB and e-CNY), or Digital Currency Electronic Payment (DCEP, ), is a central bank digital currency issued by China's central bank, the People's Bank of China. It is the first digi ...
in China, for example) will be successfully developed and implemented remains unknown. Digital currencies that are not issued by a government
monetary authority
A central bank, reserve bank, national bank, or monetary authority is an institution that manages the monetary policy of a country or monetary union. In contrast to a commercial bank, a central bank possesses a monopoly on increasing the monet ...
, such as
cryptocurrencies
A cryptocurrency (colloquially crypto) is a digital currency designed to work through a computer network that is not reliant on any central authority, such as a government or bank, to uphold or maintain it.
Individual coin ownership records ...
like
Bitcoin
Bitcoin (abbreviation: BTC; Currency symbol, sign: ₿) is the first Decentralized application, decentralized cryptocurrency. Based on a free-market ideology, bitcoin was invented in 2008 when an unknown entity published a white paper under ...
, are different because their value is market-dependent and has no
safety net
A safety net is a type of net (device), net designed to protect people from injury after falling (accident), falling from heights by limiting the distance they fall, and dissipating the impact energy. The term also refers to devices for arres ...
. Various countries have expressed concern about the opportunities that cryptocurrencies create for illegal activities such as
scams,
ransomware
Ransomware is a type of malware that Encryption, encrypts the victim's personal data until a ransom is paid. Difficult-to-trace Digital currency, digital currencies such as paysafecard or Bitcoin and other cryptocurrency, cryptocurrencies are com ...
(
extortion
Extortion is the practice of obtaining benefit (e.g., money or goods) through coercion. In most jurisdictions it is likely to constitute a criminal offence. Robbery is the simplest and most common form of extortion, although making unfounded ...
),
money laundering
Money laundering is the process of illegally concealing the origin of money obtained from illicit activities (often known as dirty money) such as drug trafficking, sex work, terrorism, corruption, and embezzlement, and converting the funds i ...
and
terrorism
Terrorism, in its broadest sense, is the use of violence against non-combatants to achieve political or ideological aims. The term is used in this regard primarily to refer to intentional violence during peacetime or in the context of war aga ...
. In 2014, the United States
IRS
The Internal Revenue Service (IRS) is the revenue service for the Federal government of the United States, United States federal government, which is responsible for collecting Taxation in the United States, U.S. federal taxes and administerin ...
advised that virtual currency is treated as
property
Property is a system of rights that gives people legal control of valuable things, and also refers to the valuable things themselves. Depending on the nature of the property, an owner of property may have the right to consume, alter, share, re ...
for federal
income-tax purposes, and it provides examples of how long-standing tax principles applicable to transactions involving property apply to virtual currency.
History
Early currency
Originally, currency was a form of receipt, representing grain stored in temple granaries in
Sumer
Sumer () is the earliest known civilization, located in the historical region of southern Mesopotamia (now south-central Iraq), emerging during the Chalcolithic and Early Bronze Age, early Bronze Ages between the sixth and fifth millennium BC. ...
in ancient
Mesopotamia
Mesopotamia is a historical region of West Asia situated within the Tigris–Euphrates river system, in the northern part of the Fertile Crescent. Today, Mesopotamia is known as present-day Iraq and forms the eastern geographic boundary of ...
and in
Ancient Egypt
Ancient Egypt () was a cradle of civilization concentrated along the lower reaches of the Nile River in Northeast Africa. It emerged from prehistoric Egypt around 3150BC (according to conventional Egyptian chronology), when Upper and Lower E ...
. In this first stage of currency, metals were used as symbols to represent value stored in the form of commodities. This formed the basis of trade in the
Fertile Crescent
The Fertile Crescent () is a crescent-shaped region in the Middle East, spanning modern-day Iraq, Israel, Jordan, Lebanon, Palestine, and Syria, together with northern Kuwait, south-eastern Turkey, and western Iran. Some authors also include ...
for over 1500 years. However, the
collapse of the Near Eastern trading system pointed to a flaw: in an era where there was no place that was safe to store value, the value of a circulating medium could only be as sound as the forces that defended that store. A trade could only reach as far as the credibility of that military. By the late
Bronze Age
The Bronze Age () was a historical period characterised principally by the use of bronze tools and the development of complex urban societies, as well as the adoption of writing in some areas. The Bronze Age is the middle principal period of ...
, however, a series of
treaties had established safe passage for merchants around the
Eastern Mediterranean
The Eastern Mediterranean is a loosely delimited region comprising the easternmost portion of the Mediterranean Sea, and well as the adjoining land—often defined as the countries around the Levantine Sea. It includes the southern half of Turkey ...
, spreading from
Minoan Crete
Crete ( ; , Modern Greek, Modern: , Ancient Greek, Ancient: ) is the largest and most populous of the Greek islands, the List of islands by area, 88th largest island in the world and the List of islands in the Mediterranean#By area, fifth la ...
and
Mycenae in the northwest to
Elam and
Bahrain
Bahrain, officially the Kingdom of Bahrain, is an island country in West Asia. Situated on the Persian Gulf, it comprises a small archipelago of 50 natural islands and an additional 33 artificial islands, centered on Bahrain Island, which mak ...
in the southeast. It is not known what was used as a currency for these exchanges, but it is thought that
oxhide-shaped ingots of copper, produced in
Cyprus
Cyprus (), officially the Republic of Cyprus, is an island country in the eastern Mediterranean Sea. Situated in West Asia, its cultural identity and geopolitical orientation are overwhelmingly Southeast European. Cyprus is the List of isl ...
, may have functioned as a currency.
It is thought that the increase in piracy and raiding associated with the
Bronze Age collapse, possibly produced by the
Peoples of the Sea, brought the trading system of oxhide ingots to an end. It was only the recovery of Phoenician trade in the 10th and 9th centuries BC that led to a return to prosperity, and the appearance of real coinage, possibly first in
Anatolia
Anatolia (), also known as Asia Minor, is a peninsula in West Asia that makes up the majority of the land area of Turkey. It is the westernmost protrusion of Asia and is geographically bounded by the Mediterranean Sea to the south, the Aegean ...
with
Croesus of
Lydia
Lydia (; ) was an Iron Age Monarchy, kingdom situated in western Anatolia, in modern-day Turkey. Later, it became an important province of the Achaemenid Empire and then the Roman Empire. Its capital was Sardis.
At some point before 800 BC, ...
and subsequently with the
Greeks
Greeks or Hellenes (; , ) are an ethnic group and nation native to Greece, Greek Cypriots, Cyprus, Greeks in Albania, southern Albania, Greeks in Turkey#History, Anatolia, parts of Greeks in Italy, Italy and Egyptian Greeks, Egypt, and to a l ...
and
Persians. In Africa, many forms of value store have been used, including beads, ingots,
ivory, various forms of weapons, livestock, the
manilla currency,
shell money, and ochre and other earth oxides. The manilla rings of
West Africa
West Africa, also known as Western Africa, is the westernmost region of Africa. The United Nations geoscheme for Africa#Western Africa, United Nations defines Western Africa as the 16 countries of Benin, Burkina Faso, Cape Verde, The Gambia, Gha ...
were one of the currencies used from the 15th century onwards to sell slaves.
African currency is still notable for its variety, and in many places, various forms of
barter still apply.
Coinage
The prevalence of metal coins possibly led to the metal itself being the store of value: first copper, then both
silver
Silver is a chemical element; it has Symbol (chemistry), symbol Ag () and atomic number 47. A soft, whitish-gray, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. ...
and
gold
Gold is a chemical element; it has chemical symbol Au (from Latin ) and atomic number 79. In its pure form, it is a brightness, bright, slightly orange-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal ...
, and at one point also bronze. Today other non-precious metals are used for coins. Metals were mined, weighed, and stamped into coins. This was to assure the individual accepting the coin that he was getting a certain known weight of precious metal. Coins could be counterfeited, but the existence of standard coins also created a new
unit of account
In economics, unit of account is one of the functions of money. A unit of account is a standard numerical monetary unit of measurement of the market value of goods, services, and other transactions. Also known as a "measure" or "standard" of ...
, which helped lead to
banking
A bank is a financial institution that accepts Deposit account, deposits from the public and creates a demand deposit while simultaneously making loans. Lending activities can be directly performed by the bank or indirectly through capital m ...
.
Archimedes' principle provided the next link: coins could now be easily tested for their
fine weight of the metal, and thus the value of a coin could be determined, even if it had been shaved, debased or otherwise tampered with (see
Numismatics
Numismatics is the study or collection of currency, including coins, tokens, paper money, medals, and related objects.
Specialists, known as numismatists, are often characterized as students or collectors of coins, but the discipline also inclu ...
).
Most major economies using coinage had several tiers of coins of different values, made of copper, silver, and gold. Gold coins were the most valuable and were used for large purchases, payment of the military, and backing of state activities. Units of account were often defined as the value of a particular type of gold coin. Silver coins were used for midsized transactions, and sometimes also defined a unit of account, while coins of copper or silver, or some mixture of them (see
debasement
A debasement of coinage is the practice of lowering the intrinsic value of coins, especially when used in connection with commodity money, such as gold or silver coins, while continuing to circulate it at face value. A coin is said to be debased ...
), might be used for everyday transactions. This system had been used in ancient
India
India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...
since the time of the
Mahajanapadas
The Mahājanapadas were sixteen Realm, kingdoms and aristocracy, aristocratic republics that existed in ancient India from the sixth to fourth centuries BCE, during the History of India#Second urbanisation (c. 600 – 200 BCE), second urbanis ...
. The exact ratios between the values of the three metals varied greatly between different eras and places; for example, the opening of silver mines in the
Harz
The Harz (), also called the Harz Mountains, is a highland area in northern Germany. It has the highest elevations for that region, and its rugged terrain extends across parts of Lower Saxony, Saxony-Anhalt, and Thuringia. The name ''Harz'' der ...
mountains of
central Europe
Central Europe is a geographical region of Europe between Eastern Europe, Eastern, Southern Europe, Southern, Western Europe, Western and Northern Europe, Northern Europe. Central Europe is known for its cultural diversity; however, countries in ...
made silver relatively less valuable, as did the flood of
New World
The term "New World" is used to describe the majority of lands of Earth's Western Hemisphere, particularly the Americas, and sometimes Oceania."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: ...
silver
after the Spanish conquests. However, the rarity of gold consistently made it more valuable than silver, and likewise silver was consistently worth more than copper.
Paper money
In
premodern China, the need for lending and for a medium of exchange that was less physically cumbersome than large numbers of
copper
Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orang ...
coins led to the introduction of
paper money, i.e.
banknote
A banknote or bank notealso called a bill (North American English) or simply a noteis a type of paper money that is made and distributed ("issued") by a bank of issue, payable to the bearer on demand. Banknotes were originally issued by commerc ...
s. Their introduction was a gradual process that lasted from the late
Tang dynasty
The Tang dynasty (, ; zh, c=唐朝), or the Tang Empire, was an Dynasties of China, imperial dynasty of China that ruled from 618 to 907, with an Wu Zhou, interregnum between 690 and 705. It was preceded by the Sui dynasty and followed ...
(618–907) into the
Song dynasty
The Song dynasty ( ) was an Dynasties of China, imperial dynasty of China that ruled from 960 to 1279. The dynasty was founded by Emperor Taizu of Song, who usurped the throne of the Later Zhou dynasty and went on to conquer the rest of the Fiv ...
(960–1279). It began as a means for merchants to exchange heavy coinage for
receipt
A receipt (also known as a packing list, packing slip, packaging slip, (delivery) docket, shipping list, delivery list, bill of the parcel, Manifest (transportation), manifest, or customer receipt) is a document acknowledging that something h ...
s of deposit issued as
promissory note
A promissory note, sometimes referred to as a note payable, is a legal instrument (more particularly, a financing instrument and a debt instrument), in which one party (the ''maker'' or ''issuer'') promises in writing to pay a determinate sum of ...
s by
wholesalers' shops. These notes were valid for temporary use in a small regional territory. In the 10th century, the
Song dynasty
The Song dynasty ( ) was an Dynasties of China, imperial dynasty of China that ruled from 960 to 1279. The dynasty was founded by Emperor Taizu of Song, who usurped the throne of the Later Zhou dynasty and went on to conquer the rest of the Fiv ...
government began to circulate these notes amongst the traders in its
monopolized salt industry. The Song government granted several shops the right to issue banknotes, and in the early 12th century the government finally took over these shops to produce state-issued currency. Yet the banknotes issued were still only locally and temporarily valid: it was not until the mid 13th century that a standard and uniform government issue of paper money became an acceptable nationwide currency. The already widespread methods of
woodblock printing and then
Bi Sheng's
movable type
Movable type (US English; moveable type in British English) is the system and technology of printing and typography that uses movable Sort (typesetting), components to reproduce the elements of a document (usually individual alphanumeric charac ...
printing by the 11th century were the impetus for the mass production of paper money in premodern China.

At around the same time in the
medieval Islamic world, a vigorous
monetary economy was created during the 7th–12th centuries on the basis of the expanding levels of circulation of a stable high-value currency (the
dinar
The dinar () is the name of the principal currency unit in several countries near the Mediterranean Sea, with a more widespread historical use. The English word "dinar" is the transliteration of the Arabic دينار (''dīnār''), which was bor ...
). Innovations introduced by Muslim economists, traders and merchants include the earliest uses of
credit,
cheques,
promissory note
A promissory note, sometimes referred to as a note payable, is a legal instrument (more particularly, a financing instrument and a debt instrument), in which one party (the ''maker'' or ''issuer'') promises in writing to pay a determinate sum of ...
s,
savings account
A savings account is a bank account at a retail banking, retail bank. Common features include a limited number of withdrawals, a lack of cheque and linked debit card facilities, limited transfer options and the inability to be overdrawn. Traditi ...
s,
transaction accounts,
loan
In finance, a loan is the tender of money by one party to another with an agreement to pay it back. The recipient, or borrower, incurs a debt and is usually required to pay interest for the use of the money.
The document evidencing the deb ...
ing,
trusts,
exchange rate
In finance, an exchange rate is the rate at which one currency will be exchanged for another currency. Currencies are most commonly national currencies, but may be sub-national as in the case of Hong Kong or supra-national as in the case of ...
s, the transfer of credit and
debt
Debt is an obligation that requires one party, the debtor, to pay money Loan, borrowed or otherwise withheld from another party, the creditor. Debt may be owed by a sovereign state or country, local government, company, or an individual. Co ...
,
and
banking institutions for loans and
deposits.
In Europe, paper currency was first introduced on a regular basis in
Sweden
Sweden, formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic count ...
in 1661 (although
Washington Irving records an earlier emergency use of it, by the Spanish in a siege during the
Conquest of Granada). As
Sweden
Sweden, formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic count ...
was rich in copper, many copper coins were in circulation, but its relatively low value necessitated extraordinarily big coins, often weighing several kilograms.
The advantages of paper currency were numerous: it reduced the need to transport gold and silver, which was risky; it facilitated loans of gold or silver at interest, since the underlying
specie (money in the form of gold or silver coins rather than notes) never left the possession of the lender until someone else redeemed the note; and it allowed a division of currency into credit- and specie-backed forms. It enabled the sale of
investment
Investment is traditionally defined as the "commitment of resources into something expected to gain value over time". If an investment involves money, then it can be defined as a "commitment of money to receive more money later". From a broade ...
in
joint-stock companies and the redemption of those
shares in a paper.
But there were also disadvantages. First, since a note has no intrinsic value, there was nothing to stop issuing authorities from printing more notes than they had specie to back them with. Second, because this increased the money supply, it increased inflationary pressures, a fact observed by
David Hume
David Hume (; born David Home; – 25 August 1776) was a Scottish philosopher, historian, economist, and essayist who was best known for his highly influential system of empiricism, philosophical scepticism and metaphysical naturalism. Beg ...
in the 18th century. Thus paper money would often lead to an inflationary bubble, which could collapse if people began demanding hard money, causing the demand for paper notes to fall to zero. The printing of paper money was also associated with wars, and financing of wars, and therefore regarded as part of maintaining a
standing army
A standing army is a permanent, often professional, army. It is composed of full-time soldiers who may be either career soldiers or conscripts. It differs from army reserves, who are enrolled for the long term, but activated only during wars ...
. For these reasons, paper currency was held in suspicion and hostility in Europe and America. It was also addictive since the speculative profits of trade and capital creation were quite large. Major nations established
mints to print money and mint coins, and branches of their treasury to collect taxes and hold gold and silver stock.
At that time, both silver and gold were considered a
legal tender and accepted by governments for taxes. However, the
instability in the exchange rate between the two grew over the course of the 19th century, with the increases both in the supply of these metals, particularly silver, and in trade. The parallel use of both metals is called
bimetallism
Bimetallism, also known as the bimetallic standard, is a monetary standard in which the value of the monetary unit is defined as equivalent to certain quantities of two metals, typically gold and silver, creating a fixed Exchange rate, rate of ...
, and the attempt to create a
bimetallic standard where both gold and silver backed currency remained in circulation occupied the efforts of
inflation
In economics, inflation is an increase in the average price of goods and services in terms of money. This increase is measured using a price index, typically a consumer price index (CPI). When the general price level rises, each unit of curre ...
ists. Governments at this point could use currency as an instrument of policy, printing paper currency such as the United States
greenback, to pay for military expenditures. They could also set the terms at which they would redeem notes for specie, by limiting the amount of purchase, or the minimum amount that could be redeemed.
By 1900, most of the industrializing nations were on some form of
gold standard
A gold standard is a backed currency, monetary system in which the standard economics, economic unit of account is based on a fixed quantity of gold. The gold standard was the basis for the international monetary system from the 1870s to the ...
, with paper notes and silver coins constituting the circulating medium. Private
bank
A bank is a financial institution that accepts Deposit account, deposits from the public and creates a demand deposit while simultaneously making loans. Lending activities can be directly performed by the bank or indirectly through capital m ...
s and governments across the world followed
Gresham's law: keeping the gold and silver they received but paying out in notes. This did not happen all around the world at the same time, but occurred sporadically, generally in times of war or financial crisis, beginning in the early 20th century and continuing across the world until the late 20th century, when the regime of floating fiat currencies came into force. One of the last countries to break away from the gold standard was the United States in 1971, an action which was known as the
Nixon shock. No country has an enforceable gold standard or
silver standard currency system.
Banknote era
A
banknote
A banknote or bank notealso called a bill (North American English) or simply a noteis a type of paper money that is made and distributed ("issued") by a bank of issue, payable to the bearer on demand. Banknotes were originally issued by commerc ...
or a bill is a type of currency and it is commonly used as legal tender in many jurisdictions. Together with
coin
A coin is a small object, usually round and flat, used primarily as a medium of exchange or legal tender. They are standardized in weight, and produced in large quantities at a mint in order to facilitate trade. They are most often issued by ...
s, banknotes make up the
cash form of a currency. Banknotes were initially mostly paper, but Australia's
Commonwealth Scientific and Industrial Research Organisation
The Commonwealth Scientific and Industrial Research Organisation (CSIRO) is an Australian Government agency that is responsible for scientific research and its commercial and industrial applications.
CSIRO works with leading organisations arou ...
developed a
polymer currency in the 1980s; it went into circulation on the nation's bicentenary in 1988. Polymer banknotes
had already been introduced in the
Isle of Man
The Isle of Man ( , also ), or Mann ( ), is a self-governing British Crown Dependency in the Irish Sea, between Great Britain and Ireland. As head of state, Charles III holds the title Lord of Mann and is represented by a Lieutenant Govern ...
in 1983.
polymer currency is used in over 20 countries (over 40 if counting commemorative issues), and dramatically increases the life span of banknotes and reduces counterfeiting.
Modern currencies

The currency used is based on the concept of
lex monetae; that a sovereign state decides which currency it shall use. (See
Fiat currency.)
Currency codes and currency symbols
In 1978 the
International Organization for Standardization
The International Organization for Standardization (ISO ; ; ) is an independent, non-governmental, international standard development organization composed of representatives from the national standards organizations of member countries.
M ...
published a system of three-digit alphabetic codes (
ISO 4217) to denote currencies. These codes are based on two initial letters allocated to a specific country and a final letter denoting a specific monetary unit of account.
Many currencies use a
currency symbol. These are not subject to international standards and are not unique: the
dollar sign in particular has many uses.
List of major world payment currencies
The following table are estimates of the 20 most frequently used currencies in world payments in April 2025 by
SWIFT.
Control and production
Commonly a
central bank
A central bank, reserve bank, national bank, or monetary authority is an institution that manages the monetary policy of a country or monetary union. In contrast to a commercial bank, a central bank possesses a monopoly on increasing the mo ...
has the exclusive power to issue all forms of currency, including coins and banknotes (
fiat money
Fiat money is a type of government-issued currency that is not backed by a precious metal, such as gold or silver, nor by any other tangible asset or commodity. Fiat currency is typically designated by the issuing government to be legal tende ...
), and to restrain the circulation alternative currencies for its own area of circulation (a country or group of countries); it regulates the production of currency by banks (
credit) through
monetary policy
Monetary policy is the policy adopted by the monetary authority of a nation to affect monetary and other financial conditions to accomplish broader objectives like high employment and price stability (normally interpreted as a low and stable rat ...
.
An
exchange rate
In finance, an exchange rate is the rate at which one currency will be exchanged for another currency. Currencies are most commonly national currencies, but may be sub-national as in the case of Hong Kong or supra-national as in the case of ...
is a price at which two currencies can be exchanged against each other. This is used for
trade
Trade involves the transfer of goods and services from one person or entity to another, often in exchange for money. Economists refer to a system or network that allows trade as a market.
Traders generally negotiate through a medium of cr ...
between the two currency zones. Exchange rates can be classified as either
floating or
fixed. In the former, day-to-day movements in exchange rates are determined by the market; in the latter, governments intervene in the market to buy or sell their currency to balance supply and demand at a static exchange rate.
In cases where a country has control of its own currency, that control is exercised either by a
central bank
A central bank, reserve bank, national bank, or monetary authority is an institution that manages the monetary policy of a country or monetary union. In contrast to a commercial bank, a central bank possesses a monopoly on increasing the mo ...
or by a
Ministry of Finance. The institution that has control of
monetary policy
Monetary policy is the policy adopted by the monetary authority of a nation to affect monetary and other financial conditions to accomplish broader objectives like high employment and price stability (normally interpreted as a low and stable rat ...
is referred to as the
monetary authority
A central bank, reserve bank, national bank, or monetary authority is an institution that manages the monetary policy of a country or monetary union. In contrast to a commercial bank, a central bank possesses a monopoly on increasing the monet ...
. Monetary authorities have varying degrees of autonomy from the governments that create them. A monetary authority is created and supported by its sponsoring government, so independence can be reduced by the legislative or executive authority that creates it.
Several countries can use the same name for their own separate currencies (for example, a ''dollar'' in
Australia
Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
,
Canada
Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...
, and the
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
). By contrast, several countries can also use the same currency (for example, the
euro
The euro (currency symbol, symbol: euro sign, €; ISO 4217, currency code: EUR) is the official currency of 20 of the Member state of the European Union, member states of the European Union. This group of states is officially known as the ...
or the
CFA franc), or one country can declare the currency of another country to be
legal tender. For example,
Panama
Panama, officially the Republic of Panama, is a country in Latin America at the southern end of Central America, bordering South America. It is bordered by Costa Rica to the west, Colombia to the southeast, the Caribbean Sea to the north, and ...
and
El Salvador
El Salvador, officially the Republic of El Salvador, is a country in Central America. It is bordered on the northeast by Honduras, on the northwest by Guatemala, and on the south by the Pacific Ocean. El Salvador's capital and largest city is S ...
have declared US currency to be legal tender, and from 1791 to 1857,
Spanish dollars were legal tender in the United States. At various times countries have either re-stamped foreign coins or used
currency boards, issuing one note of currency for each note of a foreign government held, as
Ecuador
Ecuador, officially the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on the east and south, and the Pacific Ocean on the west. It also includes the Galápagos Province which contain ...
currently does.
Each currency typically has a main currency unit (the
dollar, for example, or the
euro
The euro (currency symbol, symbol: euro sign, €; ISO 4217, currency code: EUR) is the official currency of 20 of the Member state of the European Union, member states of the European Union. This group of states is officially known as the ...
) and a fractional unit, often defined as of the main unit: 100
cents = 1
dollar, 100
centimes = 1
franc, 100 pence = 1
pound, although units of or occasionally also occur. Some currencies do not have any smaller units at all, such as the
Icelandic króna and the
Japanese yen
The is the official currency of Japan. It is the third-most traded currency in the foreign exchange market, after the United States dollar and the euro. It is also widely used as a third reserve currency after the US dollar and the euro.
Th ...
.
Mauritania
Mauritania, officially the Islamic Republic of Mauritania, is a sovereign country in Maghreb, Northwest Africa. It is bordered by the Atlantic Ocean to the west, Western Sahara to Mauritania–Western Sahara border, the north and northwest, ...
and
Madagascar
Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...
are the only remaining countries that have theoretical fractional units not based on the decimal system; instead, the
Mauritanian ouguiya is in theory divided into 5
khoums, while the
Malagasy ariary is theoretically divided into 5
iraimbilanja. In these countries, words like ''dollar'' or ''pound'' "were simply names for given weights of gold".
Due to
inflation
In economics, inflation is an increase in the average price of goods and services in terms of money. This increase is measured using a price index, typically a consumer price index (CPI). When the general price level rises, each unit of curre ...
khoums and iraimbilanja have in practice fallen into disuse. (See
non-decimal currencies for other historic currencies with non-decimal divisions.)
Currency convertibility
Subject to variation around the world, local currency can be converted to another currency or vice versa with or without central bank/government intervention. Such conversions take place in the
foreign exchange market
The foreign exchange market (forex, FX, or currency market) is a global decentralized or over-the-counter (OTC) market for the trading of currencies. This market determines foreign exchange rates for every currency. By trading volume, ...
. Based on the above restrictions or free and readily conversion features, currencies are classified as:
; Fully convertible: When there are no restrictions or limitations on the amount of currency that can be traded on the international market, and the government does not artificially impose a fixed value or minimum value on the currency in international trade. The US dollar is one of the main fully convertible currencies.
; Partially convertible: Central banks control international investments flowing into and out of a country. While most domestic transactions are handled without any special requirements, there are significant restrictions on international investing, and special approval is often required in order to convert into other currencies. The
Indian rupee and the renminbi are examples of partially convertible currencies.
; Nonconvertible: A government neither participates in the international currency market nor allows the conversion of its currency by individuals or companies. These currencies are also known as ''blocked'', e.g. the
North Korean won and the
Cuban peso.
According to the three aspects of trade in
goods and services
Goods are items that are usually (but not always) tangible, such as pens or Apple, apples. Services are activities provided by other people, such as teachers or barbers. Taken together, it is the Production (economics), production, distributio ...
, capital flows and national policies, the supply-demand relationship of different currencies determines the exchange ratio between currencies.
Trade in goods and services
Through cost transfer, goods and services circulating in the country (such as hotels, tourism, catering, advertising, household services) will indirectly affect the trade cost of goods and services and the price of export trade. Therefore, services and goods involved in
international trade are not the only reason affecting the exchange rate. The large number of international tourists and overseas students has resulted in the flow of services and goods at home and abroad. It also represents that the competitiveness of global goods and services directly affects the change of international exchange rates.
Capital flows
National currencies will be traded on international markets for investment purposes. Investment opportunities in each country attract other countries into investment programs, so that these foreign currencies become the reserves of the
central banks of each country. The exchange rate mechanism, in which currencies are quoted continuously between countries, is based on foreign exchange markets in which currencies are invested by individuals and traded or speculated by central banks and investment institutions. In addition, changes in interest rates, capital market fluctuations and changes in investment opportunities will affect the global capital inflows and outflows of countries around the world, and exchange rates will fluctuate accordingly.
National policies
The country's foreign trade, monetary and fiscal policies affect the exchange rate fluctuations. Foreign trade includes policies such as tariffs and import standards for commodity exports. The impact of
monetary policy
Monetary policy is the policy adopted by the monetary authority of a nation to affect monetary and other financial conditions to accomplish broader objectives like high employment and price stability (normally interpreted as a low and stable rat ...
on the total amount and yield of money directly determines the changes in the international exchange rate.
Fiscal policies, such as transfer payments, taxation ratios, and other factors, dominate the profitability of capital and economic development, and the ratio of national debt issuance to deficit determines the repayment capacity and credit rating of the country. Such policies determine the mechanism of linking domestic and foreign currencies and therefore have a significant impact on the generation of exchange rates.
Currency convertibility is closely linked to economic development and finance. There are strict conditions for countries to achieve currency convertibility, which is a good way for countries to improve their economies. The currencies of some countries or regions in the world are freely convertible, such as the US dollar, Australian dollar and Japanese yen. The requirements for currency convertibility can be roughly divided into four parts:
; Sound microeconomic agency
With a freely convertible currency, domestic firms will have to compete fiercely with their foreign counterparts. The development of competition among them will affect the implementation effect of currency convertibility. In addition, microeconomics is a prerequisite for macroeconomic conditions.
; The macroeconomic situation and policies are stable
Since currency convertibility is the cross-border flow of goods and capital, it will have an impact on the macro economy. This requires that the national economy be in a normal and orderly state, that is, there is no serious inflation and economic overheating. In addition, the government should use macro policies to make mature adjustments to deal with the impact of currency exchange on the economy.
; A reasonable and open economy
The maintainability of international balance of payments is the main performance of reasonable economic structure. Currency convertibility not only causes difficulties in the sustainability of international balance of payments but also affects the government's direct control over international economic transactions. To eliminate the foreign exchange shortage, the government needs adequate international reserves.
; Appropriate exchange rate regime and level
The level of exchange rate is an important factor in maintaining exchange rate stability, both before and after currency convertibility. The exchange rate of freely convertible currency is too high or too low, which can easily trigger speculation and undermine the stability of macroeconomic and financial markets. Therefore, to maintain the level of exchange rate, a proper exchange rate regime is crucial.
Alternative currencies
Distinct from centrally controlled government-issued currencies, private decentralized trust-reduced networks support alternative trading instruments (such as
Bitcoin
Bitcoin (abbreviation: BTC; Currency symbol, sign: ₿) is the first Decentralized application, decentralized cryptocurrency. Based on a free-market ideology, bitcoin was invented in 2008 when an unknown entity published a white paper under ...
and
Ethereum's ether) that describe themselves as currencies and that are classified as
cryptocurrency
A cryptocurrency (colloquially crypto) is a digital currency designed to work through a computer network that is not reliant on any central authority, such as a government or bank, to uphold or maintain it.
Individual coin ownership record ...
. With
few exceptions, these instruments are not
asset backed. The
U.S. Commodity Futures Trading Commission has declared Bitcoin (and, by extension, similar products) to be a commodity under the
Commodity Exchange Act. Historically, pseudo-currencies have also included
company scrip, a form of wages that could only be exchanged in
company stores owned by the employers. Modern
token money, such as the tokens operated by
local exchange trading systems (LETS), is a form of barter rather than being a true currency. The pseudo-currency may be Internet-based and digital: for instance,
Bitcoin
Bitcoin (abbreviation: BTC; Currency symbol, sign: ₿) is the first Decentralized application, decentralized cryptocurrency. Based on a free-market ideology, bitcoin was invented in 2008 when an unknown entity published a white paper under ...
is not tied to any specific country. Possession and sale of alternative forms of currencies is often outlawed by governments in order to preserve the legitimacy of the constitutional currency for the benefit of all citizens. For example, ArticleI, section8, clause5 of the United States Constitution delegates to
Congress the power to coin money and to regulate the value thereof. This power was delegated to Congress in order to establish and preserve a uniform standard of value and to insure a singular monetary system for all purchases and debts in the United States, public and private. Along with the power to coin money, the United States Congress has the concurrent power to restrain the circulation of money which is not issued under its own authority in order to protect and preserve the constitutional currency. It is a violation of federal law for individuals, or organizations to create private coin or currency systems to compete with the official coinage and currency of the United States.
Local currency
In economics, a local currency is a currency not backed by a national government and intended to trade only in a small area. Advocates such as
Jane Jacobs argue that this enables an economically depressed region to pull itself up, by giving the people living there a medium of exchange that they can use to exchange services and locally produced goods (in a broader sense, this is the original purpose of all money). Opponents of this concept argue that local currency creates a barrier that can interfere with
economies of scale
In microeconomics, economies of scale are the cost advantages that enterprises obtain due to their scale of operation, and are typically measured by the amount of Productivity, output produced per unit of cost (production cost). A decrease in ...
and comparative advantage and that in some cases they can serve as a means of
tax evasion
Tax evasion or tax fraud is an illegal attempt to defeat the imposition of taxes by individuals, corporations, trusts, and others. Tax evasion often entails the deliberate misrepresentation of the taxpayer's affairs to the tax authorities to red ...
.
Local currencies can also come into being when there is economic turmoil involving the national currency. An example of this is the Argentinian economic crisis of 2002 in which
IOUs issued by local governments quickly took on some of the characteristics of local currencies.
One of the best examples of a local currency is the original
LETS currency, founded on Vancouver Island in the early 1980s. In 1982, the
Canadian Central Bank's lending rates ran up to 14% which drove chartered bank lending rates as high as 19%. The resulting currency and credit scarcity left island residents with few options other than to create a local currency.
See also
Related concepts
*
Counterfeit money
*
Currency band
*
Currency transaction tax
*
Debasement
A debasement of coinage is the practice of lowering the intrinsic value of coins, especially when used in connection with commodity money, such as gold or silver coins, while continuing to circulate it at face value. A coin is said to be debased ...
*
Exchange rate
In finance, an exchange rate is the rate at which one currency will be exchanged for another currency. Currencies are most commonly national currencies, but may be sub-national as in the case of Hong Kong or supra-national as in the case of ...
*
Fiscal localism
*
Foreign currency exchange
*
Foreign exchange reserves
*
Functional currency
*
History of banking
*
History of money
*
Mutilated currency
*
Optimum currency area
*
Slang terms for money
*
Demurrage currency
*
Virtual currency
*
World currency
Accounting units
*
Currency pair
*
Currency symbol
*
Currency strength
*
European Currency Unit
*
Fictional currency
*
Franc Poincaré
*
Local currencies
*
Petrocurrency
*
Special drawing rights
Lists
*
ISO 4217
*
List of alternative names for currency
*
List of currencies
*
List of circulating currencies
*
List of proposed currencies
*
List of historical currencies
*
List of international trade topics
*
List of motifs on banknotes
Notes
References
External links
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{{Authority control
Foreign exchange market