https://www.uefa.com/uefachampionsl...-1000--new-champions-league-format-explained/
Qualification for the Champions League will continue to be open and depend on a club’s final position in the previous season’s domestic league competition. The additional four slots available in 2024/25 will be allocated according to three different criteria:
- Slot one: awarded to a club from the country placed fifth in UEFA’s national association coefficient rankings. Each association's coefficient is based on the results of its clubs’ performances in five previous Champions League and Europa League seasons.
- Slot two: awarded to the domestic league champion with the highest club coefficient among all other domestic champions that have not automatically qualified for the Champions League’s league stage.
- Slots three and four: awarded to the two clubs with the highest club coefficients that have not qualified automatically for the Champions League’s league stage, but have qualified either for the Champions League qualification phase or the Europa League/the Europa Conference League (due to start in the 2021/22 season)
Under the new format, teams will play four matches more than is currently the case. They will no longer play three opponents twice – home and away – but will instead face fixtures against 10 different teams, half of them at home and half of them away.
The top eight teams (of 36) will advance automatically to the round of 16, those sides placed between ninth and 24th will enter a play-off round. Those who finished between ninth and 16th will be seeded in the play-off draw, meaning they will face a team placed 17th to 24th – with home advantage in the second-leg match. Teams who finish 25th or lower will be eliminated, with no access to the UEFA Europa League.
The eight clubs who prevail in the play-offs will then progress to the round of 16 where they will each face one of the top-eight finishers.
From the round of 16 onward, the competition will continue to follow its existing format of knockout rounds leading to the final staged at a neutral venue selected by UEFA.