The foreign exchange market (currency, forex, or FX) trades currencies. It lets banks and other institutions easily buy and sell currencies.
The purpose of the foreign exchange market is to help international trade and investment. A foreign exchange market helps businesses convert one currency to another. For example, it permits a U.S. business to import European goods and pay Euros, even though the business's income is in U.S. dollars.
In a typical foreign exchange transaction a party purchases a quantity of one currency by paying a quantity of another currency.

The foreign exchange market is unique because of

• its trading volumes,
• the extreme liquidity of the market,
• its geographical dispersion,
• its long trading hours: 24 hours a day except on weekends
• the variety of factors that affect exchange rates.
• the low margins of profit compared with other markets of fixed income (but profits can be high due to very large trading volumes)
• the use of leverage

As such, it has been referred to as the market closest to the ideal perfect competition, notwithstanding market manipulation by central banks. According to theBank of International settlements, average daily turnover in global foreign exchange markets is estimated at $3.98 trillion. Trading in the world's main financial markets accounted for $3.21 trillion of this. This approximately $3.21 trillion in main foreign exchange market turnover was broken down as follows:

• $1.005 trillion in spot transactions
• $362 billion in outright forwards
• $1.714 trillion in foreign exchange swaps
• $129 billion estimated gaps in reporting