The Elo Rating System
How chess ratings work, from the original Elo formula to modern online adaptations used by Chess.com, Lichess, and FIDE.
Who invented the Elo system?
The Elo rating system was created by Arpad Elo, a Hungarian-American physics professor and chess master. FIDE adopted it in 1970 as the official method for ranking chess players worldwide.
Before Elo, chess rankings were subjective. His system introduced a mathematical framework where each player has a numerical rating that changes based on game results and opponent strength.
The Elo formula explained
Before the game, the system calculates each player's expected score using the rating difference. A 200-point advantage gives the stronger player about a 76% expected score. Equal ratings mean a 50-50 expectation.
The game is played. A win counts as 1, a draw as 0.5, and a loss as 0.
New Rating = Old Rating + K × (Actual Score − Expected Score). If you beat someone you were expected to beat, you gain a small number of points. If you pull an upset, you gain many more.
K controls how volatile your rating is. FIDE uses K=40 for new players (first 30 games), K=20 for established players under 2400, and K=10 for elite players (2400+). Higher K means bigger swings per game.
Chess.com vs Lichess ratings
Chess.com uses a Glicko-based system (Glicko is an evolution of Elo) with starting ratings around 400-800 depending on a placement quiz. Ratings are separate for each time control.
Lichess uses Glicko-2 with a starting rating of 1500 and a higher initial deviation, meaning early games cause larger rating changes. Lichess ratings typically run 200-300 points above Chess.com for the same player.
Neither platform uses pure Elo — both use Glicko variants that also track a "rating deviation" measuring how confident the system is in your rating.
How FIDE ratings differ
FIDE ratings are earned exclusively through over-the-board tournament play. You need at least 5 rated games against rated opponents to get an initial FIDE rating.
FIDE uses classic Elo with a rating floor of 1000 — your published rating cannot drop below this. Titled players (GM, IM, FM) have additional rating thresholds they must reach.
FIDE ratings are updated monthly (previously bimonthly), while online platforms update ratings after every game.
What do the numbers mean?
Learning the basics of tactics and piece coordination. Most players start here on Chess.com.
Understanding basic openings, simple tactics (forks, pins), and elementary endgames. About top 50% of active online players.
Consistent tactical awareness, developing opening repertoire, understanding positional concepts. Top 10-20% of active players.
Deep opening knowledge, strong calculation, endgame technique. Top 5% of active players. FIDE Candidate Master level starts at 2200.
FIDE Master (2300), International Master (2400), Grandmaster (2500). Fewer than 1% of rated players reach this level.