Disclaimer

Rook & Rating provides chess calculators and explanations for general information. Please read this page before relying on a result for a rating, a norm, a prize or a tournament decision.

Not an Official Rating or Ruling

Official FIDE ratings are calculated by FIDE from tournament reports submitted by arbiters, using the rating at the start of each rating period and FIDE's own expected-score table and rounding. Our results use the same rules with the standard logistic formula and will usually agree within a point or two, but the published list is the authority. National federations and online servers use their own systems, which our rating tools do not reproduce.

Norms Need an Arbiter

The norm calculator shows the score needed for a title-level performance. Whether a result is a norm depends on many further requirements: the event's registration, the number of games, titled and foreign opponents, rating floors and the arbiter's certificate. Only the chief arbiter and FIDE's Qualification Commission can confirm a norm.

Tiebreaks and Tournament Rules

Tiebreaks must follow the regulations published for each event. Unplayed games, byes, withdrawals and forfeits are treated differently under different versions of the rules, and pairing programs may implement them in their own way. If our result differs from the official standings, the event's published regulations and the chief arbiter decide.

Regulations Change

FIDE amends its rating, title and tiebreak regulations regularly; recent examples include the 2024 restoration of the full 400-point rule and the 2025 change for players rated 2650 and above. We update the site when we learn of changes, but there may be a delay. Check the FIDE Handbook for the current text.

Swiss Projections

Score distributions for Swiss events assume ideal pairings and no draws. Real fields bunch differently, and the projections are only a planning aid.

Time Controls

FIDE categories depend on the event's registered time control; online categories are set by each server and can change.

Errors and Changes

We test the calculators carefully, but mistakes are possible. Please report any you find to logan.luo@adsnova.cn. To the extent permitted by law, we accept no liability for decisions made on the basis of the site.