Euro banknotes and coins were put into circulation on 1 January 2002. Today the euro is the national currency of 19 of the 27 European Union (EU) member states. These 19 countries belong to the Economic and Monetary Union as a result of a European Council decision based on the fulfilment of the convergence criteria (also known as the Maastricht criteria).
These countries, which also form the eurozone, are Austria, Belgium, Cyprus, Estonia, Finland, France, Germany, Greece, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Portugal, Slovakia, Slovenia and Spain.
The EU member states outside the eurozone are Bulgaria, Croatia, the Czech Republic, Denmark, Hungary, Poland, Romania and Sweden. Denmark belongs to the Exchange Rate Mechanism II (ERM II) which means that its currency is pegged to the euro.
The euro has also been adopted as legal tender by the small states of Andorra, Monaco, San Marino and the Vatican City.