Last updated: 3 October 2026
Reviewed by Jordan Morley, FA Level 2 Football Coach
The ELO system, developed by physicist Arpad Elo for chess in the 1960s, calculates expected match outcomes and updates ratings based on actual results. The formula: expected score = 1 ÷ (1 + 10^((opponent_rating − own_rating)÷400)). The K-factor determines how much ratings move per match — higher K means faster movement. ELO has been adapted for table tennis (ITTF uses TTR, a variant), football, American football and many other sports. In table tennis, beating a higher-rated opponent gains more points; losing to a lower-rated opponent costs more.
- Developed by Arpad Elo for chess, 1960s
- Expected score = 1/(1+10^((Rb-Ra)/400))
- K-factor controls how fast ratings change
- Adapted for ITTF table tennis (TTR system)
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Originally designed for chess, Elo has been adapted across darts, table tennis, football and esports because it elegantly rewards beating stronger opponents more than beating weaker ones — a win against a much higher-rated player shifts ratings significantly, while beating a much weaker player barely moves the number.
FAQ
How does winning against a stronger opponent affect Elo rating?
You gain significantly more rating points for beating a higher-rated opponent than you would for beating someone rated similarly or lower, reflecting the unexpected nature of the result.
Is Elo rating used outside chess?
Yes — it's been widely adapted for table tennis, football club/national team rankings (like the World Football Elo Ratings), esports and other competitive one-on-one or head-to-head formats.