Enlargement of the eurozone

All member states of the European Union, except Denmark which negotiated an opt-out from the provisions, are obliged to adopt the euro as their sole currency once they meet the criteria, which include: complying with the debt and deficit criteria outlined by the Stability and Growth Pact, keeping inflation and long-term governmental interest rates below certain reference values, stabilising their currency's exchange rate versus the euro by participating in the European Exchange Rate Mechanism (ERM II), and ensuring that their national laws comply with the ECB statute, ESCB statute and articles 130+131 of the Treaty on the Functioning of the European Union.

As of 2025[update], there are 20 EU member states in the eurozone, of which the first 11 (Austria, Belgium, Finland, France, Germany, Ireland, Italy, Luxembourg, the Netherlands, Portugal and Spain) introduced the euro on 1 January 1999 when it was electronic only.

Subsequently, the following eight countries also joined the eurozone on 1 January in the mentioned year: Slovenia (2007), Cyprus (2008), Malta (2008), Slovakia (2009),[1] Estonia (2011),[2] Latvia (2014),[3] Lithuania (2015) and Croatia (2023).

All non-eurozone member states are assessed for compliance with the convergence criteria by the ECB and the European Commission biennially, with the most recent report published in June 2024.

[6] Denmark has a treaty opt-out from the obligation to join the eurozone even if it complies with all criteria; historically this also applied to the United Kingdom, until it left the EU on 31 January 2020.

As a general rule, the majority of economic experts recommend for newly accessed EU member states with a forecasted era of catching up and a past record of "macroeconomic imbalance" or "financial instability", that these countries first use some years to address these issues and ensure "stable convergence", before taking the next step to join the ERM II, and as the final step (when complying with all convergence criteria) ultimately adopt the euro.

[20] The compliance check above was conducted in June 2014, with the HICP and interest rate reference values specifically applying for the last assessment month with available data (April 2014).

As reference values for HICP and interest rates are subject for monthly changes, any EU member state with a euro derogation has the right to ask for a renewed compliance check at any time during the year.

[38][39] As of 10 August 2015, none of the remaining euro derogation states without an opt-out had entered ERM II,[40] which makes it highly unlikely that any of them will request that the European Commission conduct an extraordinary compliance check ahead of the publication of the next regular convergence report scheduled June 2016.

The European microstates of Andorra, Monaco, San Marino, and the Vatican City are not covered by convergence criteria, but by special monetary agreements that allow them to issue their own euro coins.

The first enlargements after the euro entered into circulation were to states which joined the EU in 2004; namely Slovenia in 2007, Cyprus and Malta in 2008, Slovakia in 2009, Estonia in 2011, Latvia in 2014, and Lithuania in 2015.

The chart below provides a full historical summary of exchange-rate regimes for EU members since the European Monetary System with its Exchange Rate Mechanism and the related new common currency ECU was born on 13 March 1979.

The only member state not covered by these provisions is Denmark (and formerly the United Kingdom before it withdrew from the EU), who when the euro was agreed to negotiated a treaty opt-out from the requirement to join.

[87][88] However, outgoing Finance Minister Asen Vasilev stated that preparations were so far advanced that at the current stage a caretaker government could ensure eurozone entry in 2025.

[91] It is projected that the inflation criteria will be met by the end of 2024, and if it is, the country will request an off-cycle compliance re-assessment to get approval to adopt the euro as soon as possible.

In the event that Bulgaria fulfills the price stability criterion by 31 December 2024, the government shall request approval for the country to join the eurozone on 1 July 2025.

[100] Adoption was supported under Prime Minister Bohuslav Sobotka,[101] although he accepted a recommendation from the Czech National Bank to refrain from setting a specific target date.

[110] The coalition summit resulted in a new common government policy on the issue, first cancelling the post of the just appointed euro adoption commissioner, and then instead ordering an expert panel advice by October 2024 on the merits of joining ERM-II.

Although the referendum rejected adopting the euro,[111] the country as an ERM-II member still follows the policies set forth in the EMU; meaning that Denmark policy wise aspires to meet all economic convergence criteria needed to adopt the euro, while deliberately failing only to meet the fifth legislation criteria - in full accordance with its treaty opt-out from eurozone membership.

In February 2011, newly elected Prime Minister Viktor Orbán, of the soft eurosceptic Fidesz party, made clear that he did not expect the euro to be adopted in Hungary before 1 January 2020.

[124] In April 2013, Viktor Orbán further added that Hungarian purchasing power parity weighted GDP per capita must also reach 90% of the eurozone average.

[128] In July 2016, National Economy Minister Mihály Varga suggested that the country could adopt the euro by the "end of the decade", but only if economic trends continue to improve and the common currency becomes more stable.

[153] In April 2013 Prime Minister Victor Ponta has stated that "eurozone entry remains a fundamental objective for Romania but we can't enter poorly prepared", and that 2020 was a more realistic target.

[159] In March 2018, however, members of the ruling Social Democratic Party (PSD) voted at an extraordinary congress to initially back a 2024 target year to adopt the euro as Romania's currency.

[164] The current national plan for adoption of the euro established a self-imposed criterion for Romania to reduce its structural budget deficit to 1% of GDP before entering ERM II.

[166] In February 2024, Finance Minister Marcel Boloș stated that even with the new more lenient EU fiscal rules entering into force starting from fiscal year 2025,[167] which he expected would extend the adjustment period for Romania and move the required exit of its ongoing Excessive Deficit Procedure (EDP) from 2024 to 2027, the implementation of some significant annual budget cuts amounting to 0.5% of GDP each year would still be required.

[174] However, the European Commission has previously warned Romania that failure to meet the fiscal targets of its EDP could result in the partial cancellation of ongoing payments (grants and loans) from its National Recovery and Resilience Plan for 2021-2026,[175] of which 9 out of 28.5 billion euro had been paid as of March 2024.

Former Prime Minister Fredrik Reinfeldt stated in December 2007 that there would be no new referendum until there was stable support for "yes" in the polls,[179] and this position remained unchanged in the political platform of his party Moderaterna in 2013.

If the Cyprus dispute is resolved in a manner that results in a single Cypriot state rather than formal acceptance of the status quo, the euro would become the currency of the whole island.

[223] One year later, the country had achieved compliance with the deficit criteria and had begun to decrease its debt-to-GDP ratio,[224] but still suffered from elevated HICP inflation and long-term governmental interest rates.