Interactive Elo Rating Change & Tournament Performance Calculator
Compute exact logistic expected score E_A = 1 / (1 + 10^((R_B − R_A)/400)), compare Win/Draw/Loss rating deltas across K = 10, 20, 32, and 40, and calculate multi-round Tournament Performance Rating (TPR).
1. Single-Game Elo Rating Change Calculator (K = 10, 20, 32, 40)
| K-Factor Tier | If You Win (1.0) | If Draw (0.5) | If You Lose (0.0) | New Rating (Selected Result) |
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2. Multi-Game Tournament Performance Rating (TPR) Mode
| Round | Opponent Elo | Result | Expected EA | Δ Rating (Selected K) |
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More Free Brass Pawn Chess Trainer Calculators
Interactive Chess Tactics Puzzle Board (8 Classic Motifs)
Solve 8 verified tactical puzzles directly in your browser: Royal Fork, Back-Rank Mate, Pin, Discovered Check, Skewer, Smothered & Anastasia's Mate, and Deflection.
King Opposition & Square-of-the-Pawn Endgame Visualizer
Move the White Pawn, White King, and Black King on an interactive 8×8 board to highlight the Square of the Pawn and Direct, Distant, or Diagonal Opposition.
Frequently Asked Questions
How is Expected Score calculated in the Elo rating system?
Arpad Elo's logistic curve defines Expected Score as E_A = 1 / (1 + 10^((R_B − R_A) / 400)). A 200-point rating advantage yields a 76.0% expected score; a 400-point advantage yields 90.9%.
Which FIDE K-factor applies to my rating?
FIDE uses K=40 for new players under 30 rated games and juniors under 18 rated below 2300, K=20 for established players rated below 2400, and K=10 once a player achieves 2400 Elo.
How is Tournament Performance Rating (TPR) computed?
TPR equals the average rating of your tournament opponents plus the rating difference d_p corresponding to your percentage score p: TPR = R_avg + 400 × log10(p / (1 − p)), capped at ±800 for 100% or 0% sweeps.
How do I convert tactical study into real tournament Elo gains?
Pair blunder-verification habits with structured endgame technique inside Brass Pawn Chess Trainer on iOS so you convert winning positions cleanly and hold tough draws.