Guides

How the numbers on Chess Stats are worked out, in plain language. Every figure in these guides is calculated by the same code as the tools themselves, and the US Chess formulas are checked against the worked examples in US Chess's own rating and title documents whenever the site is rebuilt.

• How US Chess Ratings Are Calculated
  Expected scores, the K-factor, the bonus, the special formula for new players, and floors — with worked numbers.
• US Chess Norms and Titles Explained
  How a norm is earned, why a perfect score against weaker players earns nothing, and the score you need.
• How FIDE Ratings Are Calculated
  FIDE’s table, its K-factors, the 400-point rule, and how a first rating is pulled toward 1800.
• How the Tournament Predictor Works
  How each game is scored, how rounds are paired, what 1,200 simulated runs tell you, and what they cannot.
• Comparing Players Through Common Opponents
  Head-to-head records, performance against a shared field, and how many games it takes to mean anything.
• When Does an Opening Score Mean Something?
  Why 6 wins from 8 games proves very little, and how many games a real edge takes to show.