Coins and Banknotes:

The euro is divided into 100 cents. All euro coins have a common side showing the denomination (value) with the EU-countries in the background and a national side showing an image specifically chosen by the country that issued the coin. Euro coins from any country may be freely used in any nation which has adopted the euro.

The euro coins are €2, €1, 50c, 20c, 10c, 5c, 2c and 1c. The two smallest denominations are no longer struck in the Netherlands or Finland, where cash transactions are rounded to the nearest five cents, but they remain legal tender there.

Commemorative coins of various other denominations, not intended for circulation, have been issued. They are legal tender only in the nation which issued them. In addition, members have from time to time replaced the national side of the two euro coin with a commemorative design--as Greece did for the 2004 Summer Olympics. Such coins are legal tender throughout the eurozone. All euro banknotes have a common design for each denomination on both sides. Notes are issued in €500, €200, €100, €50, €20, €10, €5. Some of the higher denominations, such as €500 and €200, are not issued in a few countries, though they remain legal tender throughout the eurozone.

The ECB has set up a clearing system for large euro transactions (TARGET). All intra-Eurozone transfers shall cost the same as a domestic one. This is true for retail payments, although several ECB payment methods can be used. Credit card charging and ATM withdrawals within the Eurozone are also charged as if they were domestic. The ECB has not standardized paper-based payment orders, such as cheques; these are still domestic-based.

In economic theory the degree of fulfilment of the following four criteria indicates whether an area is optimal for a monetary union. These criteria are often called the optimum currency area (OCA) criteria and are generally accepted as a reasonable metric to establish an OCA although they are not exhaustive and far from absolute. There are three economic criteria (labour and capital mobility, product diversification, and openness) and one political criterion. Since establishing a single currency over a region necessitates surrendering the ability to tailor monetary policy to specific local conditions, these four characteristics measure the ability of the economy to smooth local economic movements in the absence of monetary policy.