How many countries will make up the EU after the UK leaves?

The European Union (EU) is comprised of member countries, and after the United Kingdom officially left the EU on January 31, 2020, the total number of member countries decreased. Before Brexit, there were 28 member countries, and with the UK's departure, the count became 27. Therefore, the correct answer indicating the new total number of countries remaining in the EU after the UK leaves is indeed 27. This number reflects the current composition of the EU as it stands post-Brexit, confirming that the union continues with its remaining members without the UK.