Calculators Suite
National ELO Converter
Convert national federation ratings (USCF, CFC, ECF, DWZ) back and forth into estimated FIDE equivalents.
FIDE Elo Calculator
Calculate your new FIDE rating and performance rating instantly
How FIDE Rating Calculations Work
The FIDE rating system, developed by Professor Arpad Elo, calculates rating changes based on the difference between your rating and your opponent's rating. The K-factor determines how much your rating can change per game.
K-Factor Guide
- K = 40: New players (under 30 rated games) or players under 18 with rating below 2300
- K = 20: Players rated below 2400 with 30+ games played
- K = 10: Players who have reached 2400+ rating at any point
Expected Score Formula
The expected score E = 1 / (1 + 10(Ropponent - Rplayer)/400). Your rating change = K × (Actual Score - Expected Score).
Tips for Accurate Calculation
- Add all tournament games individually for best accuracy
- Use the correct K-factor based on your rating and experience
- Remember that draws count as 0.5 points in the actual score
- Rating floors prevent your rating from dropping below certain thresholds