How do you know just how good one chess player is compared to another? Allow us to introduce you to: the Elo rating system!
In this post:
- What is the Elo rating system?
- How does Elo work?
- Why is Elo important?
- Elo ratings and categories
- Elo on Duolingo
What is the Elo rating system?
The Elo rating system is a system that uses a mathematical algorithm to assign a numerical value to a player’s playing strength. A player’s Elo goes up or down, depending on the relative strength of their opponent and the result of the game: win, loss, or draw.
The term is named after Hungarian-American physics professor Arpad Elo, who invented a system to determine the relative strength of chess players. Today, the most common pronunciation is Elo, although Arpad Elo’s name was pronounced closer to Elo (so it’s not an acronym—a common misconception!). His rating system was an improvement upon previous attempts, and became the modern standard for most governing chess organizations. In fact, Elo’s rating system has since been adapted for tennis, boxing, and many other sports that are also zero-sum games!
The Elo rating system was adopted by the US Chess Federation in 1960, and by the World Chess Federation (FIDE) in 1970.
How does Elo work?
Warning: some serious math terms below 🤯
The Elo rating system works by assuming that each player’s performance in a game is a normally distributed random variable, with a mean (average), and a standard deviation (how far data points differ from the mean). This means that the Elo rating system can also be thought of as a probability model (represented by a bell-shaped curve) that calculates the probability that Player A will beat Player B.
All this fancy math means that if you win a game against a similar player, your Elo goes up; if you lose the game, your Elo goes down; and if you draw the game, your Elo remains about the same.
However, if you win a game against a much lower-rated player, you may not gain very much Elo, a draw may lose you rating points depending on the difference in your respective ratings, and a loss to this much lower player will lose you more points than if you had lost to a higher-rated player.
Similarly, a win against a higher rated player will bag you more points, a loss will cost you fewer points, and a draw will likely gain you some points. Just how many points you lose or gain is calculated by the rating system’s probability model, and depends on each player’s exact Elo rating at the time of the game.
One important caveat is that Elo rating systems only apply within a closed pool of players. For instance, a chess player’s countrywide US Chess Federation (USCF) Elo rating is not directly comparable to a worldwide FIDE Elo rating, since they’re based on two different groups of chess players. (In fact, USCF Elo ratings usually run about 100 points higher than FIDE Elo ratings for chess players rated in both USCF and FIDE rating systems.) This difference between different rating pools is also seen on many online chess playing platforms—for example, some top players may be rated over 3300 on certain websites, but the highest FIDE rating ever achieved is 2882, by longtime world champion Magnus Carlsen of Norway in May 2014.
Why is Elo important?
Elo rating systems help chess players gauge their relative playing strength, estimate their future results in a game or match against another rated player, and see their improvement over time, providing a useful measuring tool for personal growth.
Even though some online platforms have developed a slight variation of the Elo system, such as the Glicko system, the influence of the original system is unmistakable. In fact, Elo became such a standard that it’s now used synonymously with “rating.” Many people simply ask “What’s your Elo?” to mean “What’s your chess rating?”
Elo ratings and categories
The lowest possible Elo rating, also known as an Elo rating floor, differs per organization or website. While FIDE only allows a minimum rating of 1400, other organizations like USCF allow ratings as low as 100. If players do not reach the minimum rating in a given organization, they are considered unrated players. However, one thing is constant: Elo is never negative, no matter how many games you lose. 😅
There is no maximum Elo rating, although Magnus Carlsen currently holds the record for the highest Elo ever achieved in tournament chess: 2882!
Elo ratings are often associated with certain titles and categories in chess. While official categories below Candidate master do differ by country, here is a table of the most common classifications:
| Rating | Category or title |
|---|---|
| ~2500+ | Grandmaster |
| ~2400-2500 | International master |
| ~2300-2400 | FIDE master |
| ~2200-2299 | Candidate master |
| 2000-2199 | Expert |
| 1800-1999 | Class A player |
| 1600-1799 | Class B player |
| 1400-1599 | Class C player |
| 1200-1399 | Class D player |
| 1000-1199 | Class E player |
| 100-999 | Novice |
Elo on Duolingo
Playing chess in matches against Oscar or other players on Duolingo gives you an Elo rating that updates after each game. However, since your Elo is specific to a given pool of players, your Duolingo Elo won’t impact your Elo rating elsewhere—and playing real-life games or on any other online platforms will never affect your Duolingo Elo!
If you’re looking to improve your Duolingo Elo, consider playing more games (on the app or in person!), reading books or articles on the subject, and solving chess puzzles geared towards your current rating level.
Rating is just a number
Your Elo is a useful metric, but it isn’t everything! Even the best players have their own unique strengths and weaknesses. So don’t worry too much about your rating—just focus on improving a little bit with every game. 💪