About Rook & Rating

Rook & Rating is a free set of chess calculators for tournament players, juniors and their parents, club organisers and arbiters. It covers the arithmetic that surrounds every rated game: how a result changes a rating, what a tournament performance was worth, what score a norm needs, how tiebreaks order a tied field, how many Swiss rounds an event needs and what category a time control falls into.

The Calculators

  • Elo Rating Calculator — rating change from a tournament with FIDE K-factors, the 400-point rule and the 700 cap.
  • Performance Rating Calculator — FIDE dp-table performance, with the linear and exact methods for comparison.
  • Title Norm Calculator — the score needed for a GM, IM, WGM or WIM norm performance.
  • Tiebreak Calculator — Buchholz, Cut-1, Median Buchholz, Sonneborn-Berger and progressive score.
  • Swiss Tournament Rounds Calculator — rounds for a single winner and the expected spread of scores.
  • Chess Time Control Calculator — FIDE and Lichess categories and the maximum length of a game.

Why We Built It

Rating and tournament rules are published, but they are spread across long regulations and change every few years. In 2024 FIDE restored the full 400-point rule and raised the rating floor; in 2025 it changed how the rule applies to the strongest players. Players and organisers end up relying on half-remembered rules. Our calculators apply the current regulations, explain the method on every page and show the working, so you can check a result yourself or show it to an arbiter.

Methods and Sources

Rating changes follow the FIDE Rating Regulations: K-factors of 40, 20 and 10, the cap on K × games of 700, and the 400-point rule for players rated below 2650. Expected scores use the standard logistic Elo formula; FIDE's own lookup table differs from it by at most about 0.01 per game. Performance ratings use FIDE's dp conversion table. Norm requirements follow the FIDE Title Regulations. Tiebreak definitions follow FIDE's tiebreak regulations, and time control categories follow the FIDE Laws of Chess, with Lichess's published categories for comparison.

Who Uses It

Players checking their rating after an event, juniors and parents tracking progress, norm candidates in the last rounds of an open, club organisers planning a tournament, and arbiters double-checking tiebreaks.

Keeping It Accurate

We test the calculators against worked examples from the regulations and from published rating lists and crosstables. When FIDE changes its rules, we update the tools and say what changed. If a result differs from an official calculation, tell us; the cause is usually a rule detail worth explaining on the page.

Independence and Funding

Rook & Rating is independent and not affiliated with FIDE, any national federation, club or chess server. It is free and supported by advertising; advertisers have no influence over the content.

Privacy

The ratings and results you enter stay in your browser and are never sent to us. See the Privacy Policy.

Contact

Corrections and suggestions: logan.luo@adsnova.cn.