There are 25 currencies currently used in the 50 countries of Europe, all of which are members of the United Nations, except Vatican City, which is an observer. All de facto present Currencies in Europe.
A currency is a medium of exchange, such as money, banknotes, and coins. In Europe, the most commonly used currency is the euro (used by 25 countries); any country entering the European Union (EU) is expected to join the eurozone when they meet the five convergence criteria. Denmark is the only EU which has been granted an exemption from using the euro. Sweden has also not adopted the Euro, although unlike Denmark, it has not formally opted out; instead, it fails to meet the ERM II (Exchange Rate Mechanism) which results in the non-use of the Euro. For countries which hope to join the eurozone, there are five guidelines that need to be followed, grouped in the Maastricht criteria.
There are nine currencies of the European Union as of 2020 used officially by member states. The euro accounts for the majority of the member states with the remainder operating independent monetary policies. Those European Union states that have adopted it are known as the eurozone and share the European Central Bank (ECB). The ECB and the national central banks of all EU countries, including those who operate an independent currency, are part of the European System of Central Banks.
The euro is the result of the European Union's project for economic and monetary union that came fully into being on 1 January 2002 and it is now the currency used by the majority of the European Union's member states, with all but Denmark bound to adopt it. It is the currency used by the institutions of the European Union and in the failed treaty on an European Constitution it was to be included with the symbols of Europe as the former currency of the European Union. The euro is also widely used by other states outside the EU.
Except for the one state with an opt out, all current and future members of the EU are obliged to adopt the Euro as their currency, thus replacing their current ones. The relationship between euro and non-euro states has been on debate both during the UK's membership (as a large opt-out state) and in light of withdrawal from the EU and how that impacts the balance of power between the countries inside and those outside the eurozone, avoiding an eurozone caucus out-voting non-euro states. Former member UK had called for the EU treaties to perceive the EU as a "multi currency union", which sparked concerns about undermining euro adoption in remaining countries, Currencies in Europe.
The euro is managed and administered by the Frankfurt-based European Central Bank (ECB) and the Eurosystem (composed of the central banks of the eurozone countries). As an independent central bank, the ECB has sole authority to set monetary policy. The Eurosystem participates in the printing, minting and distribution of notes and coins in all member states, and the operation of the eurozone payment systems.
The 1992 Maastricht Treaty obliges most EU member states to adopt the euro upon meeting certain monetary and budgetary convergence criteria, although not all states have done so. Denmark has negotiated exemptions, while Sweden (which joined the EU in 1995, after the Maastricht Treaty was signed) turned down the euro in a non-binding referendum in 2003, and has circumvented the obligation to adopt the euro by not meeting the monetary and budgetary requirements. All nations that have joined the EU since 1993 have pledged to adopt the euro in due course.