What is ELO rating in chess

The Elo rating system in chess measures a player's relative skill level based on their performance against others. Created by Arpad Elo, it predicts game outcomes and adjusts ratings accordingly. Each player has a numerical rating; higher-rated players are expected to win more often. After a match, ratings are updated using a formula that factors in the result (win, loss, or draw) and the opponent's rating. A win against a stronger opponent gains more points, while losing to a weaker one deducts more. The system is widely used by FIDE and online platforms to rank players and track progress over time.

Adopted from AI