Every result counts. Know exactly how much.
Elo changes, performance ratings, title norms, tiebreaks, Swiss rounds and time controls, worked out the way arbiters do. Every calculation runs in your browser.
Elo Rating Calculator
Work out your FIDE rating change from a tournament: expected scores, the right K-factor, the 400-point rule and the 700 cap.
Open → RpPerformance Rating Calculator
Find your tournament performance rating with the FIDE dp table, the linear method and the exact zero-change rating.
Open → Rp ≥ 2450Title Norm Calculator
See the score you need for a GM, IM, WGM or WIM norm performance, given the number of games and your opponents' average rating.
Open → Bh · SBTiebreak Calculator
Calculate Buchholz, Buchholz Cut-1, Median Buchholz, Sonneborn-Berger and progressive score from your round-by-round results.
Open → ⌈log₂ N⌉Swiss Tournament Rounds Calculator
Find how many Swiss rounds separate a single winner and see how many players to expect on each score after any number of rounds.
Open → 90 + 30″Chess Time Control Calculator
Classify a time control as blitz, rapid or standard under FIDE Laws, compare it with Lichess categories and estimate how long games will last.
Open →Calculations follow FIDE's published rating, title and tiebreak regulations. They are not official ratings, norm certificates or rulings: FIDE's lists, the event's regulations and the chief arbiter decide.