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Elo rating

GeorgeLiChessOct 19, 2026Updated Nov 7, 2026

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.

Also called: Elo

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The system is named after Arpad Elo, who designed it, and it is the basis of the FIDE rating list. 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 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.

It sits close to Puzzle rating. 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. 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. 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 set out a weekly routine for each rating range.

Related terms

  • FIDE rating

    A FIDE rating is the Elo-based number that the World Chess Federation publishes each month for players with rated games, with a published minimum of 1400, and it is the rating that FIDE titles are measured against.

  • K-factor

    The K-factor is the multiplier in an Elo-style rating update that sets how many points a rating can move after a result; a larger K makes the rating react faster.

  • Rating system

    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 performance

    A rating performance is the rating a player seems to have played at in one event, found by adding a score-based adjustment to the average rating of their opponents.

  • US Chess rating

    A US Chess rating is the number the American federation assigns a player from results in its rated events; it is separate from a FIDE rating and from ratings on chess websites, so the numbers should not be swapped.

  • Glicko rating

    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.

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