--- title: "Elo rating in chess" url: "https://georgelichess.com/glossary/elo-rating.md" canonical_url: "https://georgelichess.com/glossary/elo-rating" last_updated: "2026-11-07" type: "reference" summary: "An Elo rating is a number that estimates playing strength from results. Its central idea is that rating differences predict scores." related: ["https://georgelichess.com/glossary/fide-rating.md", "https://georgelichess.com/glossary/k-factor.md", "https://georgelichess.com/glossary/rating-system.md", "https://georgelichess.com/glossary/rating-performance.md", "https://georgelichess.com/glossary/us-chess-rating.md", "https://georgelichess.com/glossary/glicko-rating.md", "https://georgelichess.com/glossary/category/tournaments-ratings-titles.md", "https://georgelichess.com/glossary.md"] --- # Elo rating in chess > **For AI agents:** the complete index of GeorgeLiChess pages is [llms.txt](https://georgelichess.com/llms.txt). Every page is also served as markdown at its URL plus .md. An Elo rating is a number that estimates playing strength from results. Its central idea is that rating differences predict scores. An Elo rating is a number that estimates playing strength from results: the gap between two ratings predicts the expected score, and wins and losses move each player's rating up or down. The system is named after Arpad Elo, who designed it, and it is the basis of the FIDE [rating list](https://georgelichess.com/glossary/rating-list.md). Its central idea is that rating differences predict scores. FIDE publishes a table: a player rated 100 points higher is expected to score about 64 percent against a lower-rated opponent, and a gap of 200 points gives about 76 percent. After a tournament, each game contributes the difference between the actual score (1, half or 0) and the expected score. The sum is multiplied by a [development](https://georgelichess.com/glossary/development.md) coefficient, K, and rounded to the nearest whole number. K is 40 for a new player until they have completed events with at least 30 games, 20 while the rating stays under 2400, and 10 once a published rating reaches 2400. It is also 40 for players up to the end of the year of their eighteenth birthday while their rating stays under 2300. Since 1 October 2025, differences greater than 400 are counted as 400 for players rated below 2650. A 1600 in one federation's pool need not equal a 1600 in another's, so compare ratings only within one list. Use it as a rough guide to the level at which to study, and do not chase points at the expense of learning. Also called: Elo. It sits close to [Puzzle rating](https://georgelichess.com/glossary/puzzle-rating.md). A puzzle rating is a number that estimates how hard a tactical puzzle you can reliably solve, and it rises and falls as you solve or fail puzzles of known difficulty, much like a game rating. Compare it with [Glicko rating](https://georgelichess.com/glossary/glicko-rating.md). A Glicko rating is a rating that comes with an uncertainty value, the rating deviation, so that a player with few or old results can move faster than one with a long recent record. Compare it with [Rating system](https://georgelichess.com/glossary/rating-system.md). A rating system is a method that turns game results into a number for each player, rising after wins against strong opponents and falling after losses, so that strength can be compared. Rating and title terms like "Elo rating" matter once you know your next step, and the [improvement plans by rating band](https://georgelichess.com/improve.md) set out a weekly routine for each rating range. ## Related terms - [FIDE rating](https://georgelichess.com/glossary/fide-rating.md) - [K-factor](https://georgelichess.com/glossary/k-factor.md) - [Rating system](https://georgelichess.com/glossary/rating-system.md) - [Rating performance](https://georgelichess.com/glossary/rating-performance.md) - [US Chess rating](https://georgelichess.com/glossary/us-chess-rating.md) - [Glicko rating](https://georgelichess.com/glossary/glicko-rating.md) ## Guides that go further - [Chess ratings explained](https://georgelichess.com/chess-ratings-explained.md): What a rating measures, how FIDE, Lichess, US Chess and chess.com compute theirs, and why the numbers differ. - [Average chess rating and a good chess rating](https://georgelichess.com/chess-rating-percentiles.md): What share of active Lichess players are rated above 800, 1200, 1500, 1800 or 2000, by time control. - [Chess rating calculator](https://georgelichess.com/tools/rating-calculator.md): Work out how a FIDE rating changes after a run of games. ## Sources - FIDE Handbook B02 FIDE Rating Regulations (effective 1 March 2024) (Article 8), read 2026-10-21: https://handbook.fide.com/chapter/B022024 - FIDE Handbook B02 FIDE Rating Regulations (effective 1 March 2024) (Article 8.1.2), read 2026-10-21: https://handbook.fide.com/chapter/B022024 - FIDE Handbook B02 FIDE Rating Regulations (effective 1 March 2024) (Article 8.3), read 2026-10-21: https://handbook.fide.com/chapter/B022024 - FIDE Handbook B02 FIDE Rating Regulations (effective 1 March 2024) (Article 8.3.1), read 2026-10-21: https://handbook.fide.com/chapter/B022024 [Book your first lesson](https://georgelichess.com/book.md) and George Li reviews your games and builds a study plan around them. Questions about lessons: write to hello@georgelichess.com. ## Related - [FIDE rating in chess](https://georgelichess.com/glossary/fide-rating.md) - [K-factor in chess](https://georgelichess.com/glossary/k-factor.md) - [Rating system in chess](https://georgelichess.com/glossary/rating-system.md) - [Rating performance in chess](https://georgelichess.com/glossary/rating-performance.md) - [US Chess rating](https://georgelichess.com/glossary/us-chess-rating.md) - [Glicko rating in chess](https://georgelichess.com/glossary/glicko-rating.md) - [Chess terms: Tournaments, ratings and titles](https://georgelichess.com/glossary/category/tournaments-ratings-titles.md) - [Chess terms glossary: plain definitions](https://georgelichess.com/glossary.md)