What is the ELO rating ?

In chess, the Elo rating system is used to rank players based on their performance. The Elo system was developed by Arpad Elo, a Hungarian-born American physics professor and chess player. It is based on a player's performance and considers the strength of the opposition. The higher the Elo rating, the stronger the player.

To the point

But can a player's Elo rating ever reach 0? The short answer is no.
A player's Elo rating can decrease due to poor performance, but there are limits to how much it can decrease. For example, if a player with a rating of 1500 loses to someone with a rating of 1200, their rating will decrease by around 20 points. However, if the same player loses to someone with a rating of 800, their rating will only decrease by about 1 point. The reason for this is that the Elo system takes into account the relative strength of the players. A loss to a much weaker opponent is not considered as significant as a loss to a stronger opponent.

Another factor that makes it impossible to have a 0 Elo rating is that the Elo system is based on a player's entire playing history, not just their current rating. Even if a player loses every game and has a very low rating, their rating will not drop to 0. There will always be some minimum value that their rating can reach.
However, it is possible for a player's rating to be very close to 0. For example, a player who has lost many games and has a rating of 200 may be considered a beginner. They may struggle to win games against other beginners, and their rating may not increase significantly until they start winning games against stronger opponents.
It is also worth noting that the Elo system is not perfect and has its limitations. For example, it does not take into account the quality of a player's moves, only whether they win or lose. A player who wins a game due to their opponent making a blunder may receive the same rating increase as a player who wins a game with a brilliant combination. Additionally, the Elo system assumes that players have a consistent level of performance over time, which may not always be the case.

Conclusion

In conclusion, while it is not possible to have a 0 Elo rating in chess, it is possible for a player's rating to be very low. However, the Elo system takes into account the relative strength of the players, and a player's rating will not drop to 0 even if they lose many games. The Elo system is a useful tool for ranking players and determining their relative strength, but it has its limitations and should be used with caution.