Elo Rating — Arpad Elo 1960
New = Old + K × (Actual - Expected). Expected = 1/(1+10^((Rb-Ra)/400)). K=40 new, 20 standard, 10 master. Magnus Carlsen 2882. FIDE, Chess.com.
Why This Stat Matters
Why: Elo measures relative skill. 400 pts = 10:1 expected. Used in chess, esports, many games.
How: Enter your rating, opponent rating, actual score (1=win, 0.5=draw, 0=loss), K-factor. Get new rating and change.
- ●Carlsen 2882 peak
- ●K=40 new players, 20 standard, 10 master
- ●400 pts = 10:1 expected
📋 Quick Examples — Click to Load
📊 K-Factor Impact
Upset gain by K (200-pt underdog)
📈 Expected Win %
By rating difference (400 scale)
🍩 Elo Infographic
Key facts
📊 K-Factor Comparison
Upset vs expected win gain
For educational and informational purposes only. Verify with a qualified professional.
🏅 Sports Records
Magnus Carlsen peak 2882
K=40 new, 20 standard, 10 master
Expected = 1/(1+10^((Rb-Ra)/400))
The Elo rating system was created by Arpad Elo in 1960 for chess. New Rating = Old + K × (Actual - Expected). Expected = 1/(1 + 10^((Rb-Ra)/400)). K-factor: 40 for new players, 20 standard, 10 for masters. Magnus Carlsen peaked at 2882. Used in FIFA, League of Legends, Overwatch. The 400 scale factor means a 400-point gap ≈ 90% expected win.
Sources: FIDE, Chess.com, Arpad Elo 1960.
Key Takeaways
- • Elo system created by Arpad Elo in 1960 for chess; now used in FIFA, gaming.
- • Magnus Carlsen peaked at 2882, the highest Elo ever recorded.
- • K-factor controls volatility: 40 new, 20 standard, 10 master.
- • 400-point gap ≈ 90% expected win; 200 points ≈ 76%.
Did You Know?
How Does Elo Work?
Formula
Expected = 1/(1 + 10^((opponent - you)/400)). New Rating = Old + K × (Actual - Expected). Actual is 1 (win), 0.5 (draw), 0 (loss).
K-Factor
K=40: New players, rapid adjustment. K=20: Established. K=10: Masters, stable. FIDE uses 40 for <2400, 10 for 2400+.
Upsets
Beating a higher-rated player yields more points—your actual (1) exceeds expected. Losing to a lower-rated player costs more.
Expert Tips
K-Factor Comparison
| K | Use Case | Upset Gain (200 pts) |
|---|---|---|
| 40 | New players | ~32 |
| 20 | Standard | ~16 |
| 10 | Master | ~8 |
Frequently Asked Questions
What is the Elo rating system?
The Elo system was created by Arpad Elo in 1960 for chess. New Rating = Old + K × (Actual - Expected). Expected = 1/(1 + 10^((Rb-Ra)/400)). It measures relative skill and predicts match outcomes. Used by FIDE, Chess.com, FIFA, and video games like League of Legends.
What is the K-factor in Elo?
K-factor controls rating volatility. K=40 for new players (rapid changes), K=20 for established players, K=10 for masters (stable). Higher K = bigger swings per game. FIDE uses K=40 for players under 2400 and K=10 for 2400+.
What is Magnus Carlsen's peak Elo?
Magnus Carlsen peaked at 2882 Elo in May 2014, the highest ever. Garry Kasparov held 2851. The 400 in the formula is a scale factor—a 400-point gap means the higher-rated player is expected to win ~90% of games.
Where is Elo used besides chess?
Elo is used in FIFA rankings, League of Legends, Overwatch, tennis, and many competitive games. The same formula applies: expected score, actual score, K-factor. Each system may use different K and scale factors.
How does the 400 scale factor work?
Expected = 1/(1 + 10^((opponent - you)/400)). A 400-point gap means ~90% expected win. 200 points = ~76%. 100 points = ~64%. The 400 makes the curve match real-world win rates in chess.
What happens when you beat a higher-rated player?
You gain more points—your actual (1) exceeds your expected (<0.5). Beating a 200-point higher opponent with K=20 gains ~16 points. Losing to a much lower-rated player costs more points.
Key Statistics
Official Data Sources
⚠️ Disclaimer: This calculator is for educational purposes only. Different organizations (FIDE, Chess.com, etc.) use variations of the Elo formula. Not official rating advice.