What date did each european country convert to the euro currency?

Eurozone Countries
From January 1st, 2002, twelve of the fifteen European Union members will complete their conversion to using the Euro instead of their own national currencies. These twelve states comprise the Eurozone, sometimes called Euroland.

Conversion Timetable
The 12 countries in the euro zone changed over to the single currency on 1 January 1999. This means that the euro became their only legal currency and their old national currencies became sub-units of the euro. The last phase of the changeover will be 1 January 2002 when euro notes and coins go into circulation and the authorities start to withdraw the old national currency in each member of the euro zone. When this is largely completed, notes and coins in national currency units will no longer be legal tender. In most countries, this should be around 28 February.

Conversion Rules
National currencies in participating countries have been sub-units of the euro since 1 January 1999, apart from Greece which only qualified in January 2001. Conversion into euros is regulated by a law passed at European Union level in 1997. This says that only the rate fixed for each national currency unit on 1 January 1999 can be used to convert into euros. Use of any other rate would be a breach of the law. Each conversion rate must be used to six significant figures to achieve the fairest outcome on rounding for both sides of any transaction e.g 1 euro = 40.3399 BEF. The same 1997 law also lays down on the rounding of odd amounts after conversion. If the number at the third decimal place is less than 5, then the euro figure must be rounded down e.g. 34.874 euros becomes 34.87. If the third decimal number is five or above, then it can be rounded up e.g. 34.875 becomes 34.88 euros.