which country does not use the euro as its currency

As of 2021, there are 27 European Union countries, however, not all of them use the euro as their currency. The countries that do not use the euro are:

1. Bulgaria
2. Croatia
3. Czech Republic
4. Denmark
5. Hungary
6. Poland
7. Romania
8. Sweden

Note: While Bulgaria, Croatia, and Romania are EU members, they have not yet met all the necessary criteria to adopt the euro as their currency.