The difference between the ratings of the winner and loser determines the total number of points gained or lost after a game.

After every game, the winning player takes points from the losing one. A player whose rating is 100 points greater than their opponent's is expected to score 64% if the difference is 200 points, then the expected score for the stronger player is 76%.Ī player's Elo rating is represented by a number which may change depending on the outcome of rated games played. Two players with equal ratings who play against each other are expected to score an equal number of wins. The difference in the ratings between two players serves as a predictor of the outcome of a match. The Elo system was originally invented as an improved chess-rating system over the previously used Harkness system, but is also used as a rating system in association football, American football, basketball, Major League Baseball, table tennis, board games such as Scrabble and Diplomacy, and esports, particularly Counter Strike: Global Offensive and League of Legends. It is named after its creator Arpad Elo, a Hungarian-American physics professor. The Elo rating system is a method for calculating the relative skill levels of players in zero-sum games such as chess. Arpad Elo, the inventor of the Elo rating system