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ELO Rating System

The ELO rating system is a method used to calculate the relative skill levels of players in competitive games. Developed by Arpad Elo, this system is widely used in games such as chess. On we use it for games including Tic-Tac-Toe, connect 4, gomoku, chess, and battleship. This guide will explain how the ELO system works and how it affects your ranking in a way that's easy to understand.

What is the ELO Rating System?

The ELO rating system assigns a numerical value to a player's skill level based on their performance in games. This rating changes after each match to reflect the player's performance.

Key Concepts of the ELO System

  1. Initial Rating: New players start with a base rating, which might be different depending on the game or platform. For example, a new player might begin with a rating of 1200.
  2. Rating Adjustments: After each game, players' ratings are adjusted. How much your rating changes depends on the outcome of the match and the ratings of both players.
  3. Expected Outcome: Before a match, the system calculates the expected outcome based on the players' ratings. If you're playing against someone with a higher rating, they are expected to win. If you beat them, you'll gain more points because you surpassed expectations.
  4. K-Factor: This number affects how much your rating changes after a game. A higher K-factor means your rating will change more dramatically with each win or loss, while a lower K-factor means smaller changes.

How Ratings Change

When you win a game, your rating goes up. The amount it increases depends on the difference between your rating and your opponent's rating. If you beat someone with a higher rating, your rating will increase more than if you beat someone with a lower rating. Conversely, if you lose to someone with a lower rating, your rating will decrease more than if you lose to someone with a higher rating.

Example Scenario

Imagine you're a new player with a rating of 1200, and you play against an opponent with a rating of 1300:

  • If you win: Your rating will increase significantly because you beat someone with a higher rating.
  • If you lose: Your rating will decrease, but not by as much, because the higher-rated player was expected to win.
  • If you draw: Both players' ratings will adjust slightly, reflecting that the match was closer than expected.

Why the ELO System is Important

The ELO rating system helps create fair and balanced matches by pairing players of similar skill levels. It also provides a clear measure of a player's improvement over time. The dynamic nature of the system ensures that as you play more games, your rating will more accurately reflect your true skill level.


The ELO rating system is a fair and efficient way to rank players in competitive games. By understanding how it works, you can better appreciate the changes in your rating and set goals to improve your performance. Whether you're playing Tic-Tac-Toe, Connect 4, Gomoku, Chess, or Battleship, the ELO system on helps keep the competition exciting and meaningful.

Ready to test your skills? Head over to and see how you stack up against other players!