If you have played a game of online chess, or queued up in ranked esports games, chances are you’ve already encountered the Elo rating system.
Originally developed in the 1960s by physics professor and chess player Arpad Elo, this system was designed to calculate the skill levels of players based on their performance. It quickly became the global standard for rating chess players and has since found its way into video games, sports leagues, and even artificial intelligence (AI).
How does it work?
At its core, Elo is a numbers game. When two players face off, the system looks at their current ratings and calculates how many points they gain or lose depending on the match outcome. If you beat someone stronger than you, your score gets a big boost. If you lose to a weaker player, your rating takes a hit. Even a draw can shift your score, depending on your opponent’s strength.
Before Elo’s system, players were rated using the “Harkness system”, which wasn’t very accurate. Elo stepped in with a model based on statistics and probability, and the result was revolutionary.
The beauty of the Elo system lies in how dynamic and self-correcting it is. It constantly updates as you play, giving a more accurate sense of where you stand. That’s what makes it so popular across platforms.
Beyond chess
Today, Elo or its modified versions are used far beyond chess. Competitive games like League of Legends and FIFA use it to match players. Sports analytics teams rely on it to rank football clubs, and tennis players. Even AI researchers use Elo ratings to measure how “smart” a bot is.
And for a while, popular dating app Tinder even used a version of the Elo score to rank users based on profile performance.
More than 60 years since it was invented, the Elo system continues to shape how we compete, rank, and compare in games, sports, and beyond.
